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Air Brake Tests 

Compiled 

and 

Publisljed by 

THE WESTINGHOUSE 

AIR BRAKE 

COMPANY 



^ 



In Connection with ITS 
EXHIBIT OF BRAKING AP- 
PLIANCES at the LOUISIANA 
PURCHASE EXPOSITION 

MCMIV 



Copyright, 1904, by 
THE WESTINGHOUSE AIR BRAKE COMPANY, 

WiLMERDING, Pa. 







U6RARV nf OONGRESSJ 
Two Ooolcs Rere^vwl 

SEP 2 1904 
Oopyrlfht Entry 

CLASS ^ XXo. Na | 




INDEX. 

PAGE 

The Growth of Car Braking, i ^ 

Galton-Westinghouse Tests, 21 

Paris and Lyons Railway Tests, 102 

The Burlington Trials (C, B. & Q, R. R.), . . ., 116 

Westinghouse Freight Train Trials, 231 

The Karner Trials (N. Y. C. & H. R. R. R.), . . . 236 

Sang Hollow Tests (P. R. R.), 276 

Shiproad Tests (P. R. R.), 285 

Nashville Locomotive Brake Tests, 287 

Absecon Tests (P. R. R.), 291 

Atsion Tests (C. R. R. of N. J.), 314 



)0( 



ILLUSTRATIONS 



PAGE 



George Westinghouse, Frontispiece 

The Old ^'Diligence" and Its Brake, 12 

Primitive Forms of Car Brakes, 16 

The Stevenson Steam Locomotive Brake, 20 

GALTON-WESriNGHOUSE TESTS. 

Galton-Westinghouse Dynamometers, 24 

General Arrangement of Brake Van, . . . . . 27-29 
Diagrams, Experiments i to 9 Inclusive, . . . . 31-38 

Altered Arrangement of Brake Van, 42, 43 

Diagrams, Experiments 10 to 25 Inclusive, , . . 47-68 

Diagrams on Skidding, 76 

Diagrams Coefficient of Friction, 79 

Brake-Block Pressure Regulator, 83-85 

Diagrams Made With Pressure Regulator, . . . 88-90 

Diagram Showing Slow Application, 94 

Diagram Showing Advantage of Applying Brakes to 

Every Wheel of a Train, 95 

Diagrams of Paris and Lyons Railway Tests, . . . 107-110 

burlington trials. 

Profile and Plan of Track, . . . 118 

Westinghouse Brake Apparatus, 120-124, ^74 

Eames Brake Apparatus, 126-129, ^74^ ^75 

The American Brake Apparatus, . 130 

The Widdefield & Button Brake Apparatus, . . . . 130 

The Rote Brake Apparatus, 132 

Boyer Speed Recording Apparatus, 132 

Dynamometer Car Diagrams, 134, 137, 157 

The Autographic Recording Apparatus, 136 

Foundation Brake Gear, 1 49-1 51, 199-219 

Down Grade Diagrams, . . 155, 157, 159, 220, 222, 224 
Carpenter Brake Apparatus, 179-184, 188 



ILLUSTRATIONS. 



PAGE 



Card Brake Apparatus, 185-188 

Middle Car Diagrams, 226-230 

karner trials. 

The Karner Trial Trains, 236 

The Tripping Device, 238 

Diagrams of Service Application, 244 

Diagrams of Emergency Application, 246 

Curves of Stops, 257-269 

absecon tests, 
Westinghouse High Speed Reducing Valve, , . 291, 292 
Curves of Stops, 297-311 

atsion tests. 

Curves of Stops, 315-321 

Brake Cylinder Diagrams, . . . . . . . . 322, 323 



)0< 



THE GROWTH OF CAR BRAKING. 




LL development of arts, mechanics and ob- 
jects of utility have grown out of the ne- 
cessity for appliances designed to accomplish 
some particular purpose, and when we look 
back over the period during which the air 
brake has developed we are apt to feel 
somewhat surprised that its inception is so 
recent, and, in fact, that the whole question 
of vehicle braking is a comparatively modern one. Knowing that the 
ancients traveled extensively,-, and that the great empires of history 
moved large armies all over the then known world, accompanied by 
trains of baggage wagons and war machines, it is natural to suppose 
that the necessity for retarding those vehicles was plainly manifested ; 
but, as a matter of fact, the first suggestion of this necessity by the use 
of a practical mechanism designed for the purpose does not appear to 
have been more than 250 years ago. The primitive carts and wagons 
which were used in agricultural work, and in connection with trans- 
portation of baggage and supplies for armies, were of such construction 
that the natural resistance to rotation of their wheels was quite sufficient 
to bring them to a stop upon ordinary roads, and in cases of steep 
grades it was always easy to chain a log or stone to the back of the 
wagon, so that by dragging it over the ground the speed of the vehicle 
was checked. 

Indeed, to find the time when the question of braking first came 
into prominence we need go no further back than the period when 
highways became sufficiently well made and maintained as to admit 
of a heavy vehicle being drawn over them at comparatively high 



THE GROWTH 

OF 

CAR BRAKING 



Air Brake Tests ^^-^^ ^^ 



speed. Country roads everywhere as late 
as 1725 were in a most deplorable con- 
dition, being narrow and full of ruts and 
stones. At this time stage coaches had been running for eighty years 
and more, while the stage wagon — the forerunner of the stage coach 
— was introduced into England in 1564. During the middle of the 
1 8 th century there was considerable agitation for better roads which 
seemed to have had a beneficial effect, since during the latter part of this 
century the first mail coaches or ^^ Diligences '' were placed upon the 
roads between London and various cities of Great Britain. These 
coaches ran at speeds much greater than had been possible before. The 
one between London and Bristol ran a distance of 1 1 7 miles in i 5 
hours, or an average of about 7^ miles an hour, which average in- 
cludes all stops for changing horses, etc., so that the maximum speed 
must have been considerably in excess of this. 

It is a noticeable fact, that with all kinds of conveyances the question 
of braking has always increased in importance as the demand for higher 
speeds increased. During the century from 1770 to 1870 there were 
granted in England about 190 patents for various kinds of braking 
appliances for common-road vehicles ; of these 46 were applied to the 
periphery of the wheel; 28 on the nave ; 27 were actuated by the 
movement of the horses ; 2 1 were applied to fly or brake wheels ; 
8 were applied to the axle ; i o were actuated by a spring ; 4 were 
automatic ; 3 electromagnetic ; 3 pneumatic ; 4 relying on momentum ; 
3 accumulated power for subsequent propulsion, etc. In America 
there had been 170 such patents, 21 of which were for automatic 
designs. 

In connection with common road vehicles it is worthy to note that 
the first devices adopted are those which have formed the basis of 
almost all brake appliances which have since been employed for the 
same kind of vehicle. The early stage coaches and even the later 
mail coaches were provided with an iron shoe which slips under the 
wheel and is chained to the forepart of the coach so as to drag both 
shoe and wheel along over the surface of the ground. This method 
of braking was one of the first devices adopted and is used extensively 



^^£1^ Air Brake Tests 



THE GROWTH 

OF 

CAR BRAKING 



to-day. The old arrangement of two 
brake blocks and a beam' with suitable 
levers connecting each to the driver was 
also early introduced, and all kinds of developments from this arrange- 
ment are seen to-day on various kinds of vehicles. 

The many patents granted referring to this subject clearly shows 
how important the question of braking had already become, and it is 
impossible to tell what the common-road vehicle of to-day would have 
been if the power of steam had not been discovered right in the 
midst of the great development of roads and road vehicles and turned 
the attention of inventors to channels which were destined to entirely 
change the relative importance of earlier modes of travel. 

The railroad was no new thing, even at this time, for so far back 
as 1630 an enterprising mine owner at Newcastle-on-Tyne, finding 
the roads between his mines and the river so bad as to seriously inter- 
fere with the hauling of coal, conceived the idea of laying in the road 
wooden rails and running thereon cars with wooden wheels. The 
tractive effort of these cars was so much decreased that the necessity 
of some contrivance to check their speed was at once apparent and 
brought out simple forms of brakes. One of these forms consisted of 
a metal tipped beam which was fastened to the frame of the car in 
such a way as to scrape along in the ground -at the side of the track. 
Another form was a simple lever pivoted to the side near the 
center of the car and ordinarily held up by a chain, which, w^hen 
desired for use, could be liberated and pressed by hand or foot against 
the top periphery of the wheel. 

There were many other simple devices adopted by the primitive 
railroads, such as the ^^Sprag'' brake, which was applied to cars of 
later construction when the wheels were made with spokes and the 
iron flange tire was appHed. The so-called '^Sprag" was a hard- 
wood stick which was thrust through the wheel underneath the frame 
of the car, thus causing the former to skid along upon the rail. 

Many other primitive forms of brakes were applied to such railroads 
as existed, but the speeds employed on these roads were generally low and 
the cars small enough to be drawn by draught animals, and the question 



THE GROWTH 

OF 

CAR BRAKING 



Air Brake Tests ^"^''^ 



was not a particularly serious one until 
the advent of the steam locomotive. The 
great revolution v^hich the knov^ledge of 
the powder and use of steam has brought about was well under way 
during the first part of the nineteenth century. During the first 70 
years of the century about 650 patents were granted in England for 
various kinds of brakes for railroad service. Of these 2 1 were for 
electro-magnetic brakes; 20 hydrostatic; 32 pneumatic; 50 steam, 
and the balance were for various other kinds, mostly hand brakes and 
different designs of the foundation brake gear. In 1833, Stevenson 
patented his steam brake, consisting simply of a small cylinder con- 
taining a piston, the rod of which connected through a system of 
levers to a cam brake. The first pneumatic brake was a vacuum 
brake patented by James Nasmyth and Charles May in 1844. In 
1848 Samuel C. Lister patented an air brake having an axle-driven 
pump and suitable reservoir to be placed on the ^^ Guard's Carriage," 
and suitable cylinder, pipe, and connections on the various cars to con- 
stitute a straight-air equipment, quite the same as that which followed 
many years after, except that it was designed to be operated by the 
guard and not by the engineer. 

Many interesting and ingenious contrivances were suggested and 
patents obtained for same. In the United States up to 1870 there had 
been granted 305 patents for railway brakes, of which 8 were auto- 
matic, 3 electro-magnetic, 5 steam, i vacuum, and 2 air brakes, 
the balance referring to various forms of foundation brake gear and 
other devices which have never stood the test of actual practice. 
Some of the various systems originating in this country were extensively 
tried and seemed to meet the conditions for which they were de- 
signed with various grades of success. The '' Cramer" brake, which 
was brought into use in 1853, consisted of a large spiral spring attached 
to the brake staff at the end of the car and which was wound up by 
the brakeman immediately after leaving a station. Attached to the 
mechanism was a cord which ran through the train to the engineer's cab 
and the brake was so designed that when the engineer pulled the cord coil 
springs on each vehicle were released and these at once wound up 




/ 





O 



^^^^ '^ Air Brake Tests 



THE GROWTH 

OF 

CAR BRAKING 



chains leading to the foundation brake 
gear, thereby bringing the brake shoes 
against the wheels. 

The ^^Loughridge Chain Brake," which came into use in 1855, 
consisted of a system of rods and chains continuously connected 
throughout the train, as follows : On each vehicle were two pairs of 
small pulleys, each pair sliding toward the other upon an iron frame- 
work, but held apart by a spring ; to each pair was connected a top rod 
leading to the foundation brake gear. Upon the engine was placed a 
drum connected by a worm and gear to a small friction wheel; 
when a lever in the engineer's cab was pulled this friction wheel 
was brought into contact wnth the periphery of one of the driving 
wheels, thereby causing the drum to wind up the chain and shorten its 
length throughout the train ; in so doing the pulleys upon each vehicle 
were brought closer together, thereby applying the brakes. 

Of course, the earlier type of hand brake underwent considerable im- 
provement as the years went on and as experience made it advisable 
and necessary. For many y-ears during the early railroading the 
majority of passenger and all freight equipment cars were braked by 
hand ; nevertheless there was a constant desire for and search after 
a practical automatic brake. These types just referred to were the 
result of much research ; there were many other forms of brake 
which attained a certain degree of prominence and were more or 
less successfully operated upon different roads throughout the country. 
We shall have occasion to mention some of these in connection with 
tests given later on. 

In 1869, the Westinghouse non-automatic air brake, which has since 

generally been designated as the ''Straight Air" brake, was brought 

out. It consisted of a very simple steam-actuated air pump placed upon 

the side of the engine, and a reservoir in which the compressed air could 

be stored. A pipe line from the reservoir was carried throughout the 

y length of the train, connections between vehicles being made by 

j means of hose and couplings. Each vehicle was provided with a simple 

I cast-iron cylinder, the piston rod of which was connected to the brake 

\ rigging in such a way that when the air was adrnitted to the cylinder 



THE GROWTH 

OF 

CAR BRAKING 



Air Brake Tests ^"^''^ 



the piston was forced out and the brakes 
thereby applied. In the engineer's cab 
there was placed in the pipe line just men- 
tioned a three-way cock, by means of which compressed air could be 
admitted to the trainpipe and thus to the cylinders on each car ; or the 
air already in the cylinders and trainpipe could be discharged to the 
atmosphere, thus releasing the brakes. This was the simplest and most 
efficient brake that had been introduced up to that time and was largely 
adopted by the American railways ; but while all that could be de- 
sired for single vehicles, the danger incident to the entire loss of brak- 
ing power when most needed, due to the bursting of hose under pressure, 
the parting of the train or other rupture of the brake system led to the 
invention of the automatic brake by Mr. George Westinghouse, proba-lj 
bly the greatest advance step ever made in the development of the art. 
The first form of this brake was introduced in 1872, and is now gen- 
erally referred to as the ^^ plain automatic." The essential difference 
between this brake and the straight-air type which it promptly super- 
seded consisted in the installation of supplementary or auxiliary reservoirs 
for the storage of compressed air on the cars in addition to the main 
reservoir on the locomotive, so that each vehicle carried its own supply, 
and the employment of a most ingenious valve mechanism by means of 
which the application of the brake was caused by the reduction of air 
pressure in the trainpipe, whether such reduction was made intention- 
ally or as the result of accident. The device by means of which this 
arrangement was made possible was called a *^ triple valve," because of 
its three-fold function of applying the brake, releasing it, and recharg- 
ing the auxiliary reservoir. In this triple valve was a slide valve 
attached to a piston, so placed that trainpipe pressure was always on 
one side of it and auxiliary reservoir pressure on the other. When $ 
trainpipe pressure exceeded auxihary reservoir pressure the piston and I 
slide valve took such position that air could flow from the trainpipe into 
the auxiliary reservoir, at the same time opening a port leading from the 
brake cylinder to the atmosphere ; if the trainpipe pressure was re- 
duced below that of the auxiliary reservoir, the piston and slide valve 
moved to another position in which air could flow from the auxiliary 



P^'seiQ Air Brake Tests 



THE GROWTH 

OF 

CAR BRAKING 



reservoir into the brake cylinder and 
apply the brakes. The operation of the 
brakes throughout the train was thus 
under the entire control of the engineer through the medium of train- 
pipe pressure actuating the triple valve on each vehicle. A reduction 
of trainpipe pressure applied the brakes, v^hile the restoration of normal 
pressure by allowing air to flow from the main reservoir into the train- 
pipe released them. 

The three-way cock in the engineer's cab was replaced by a more 
elaborate valve known as an engineer's brake valve. The necessity 
for this substitution was due to the fact that in applying the brakes the 
reduction of pressure in the trainpipe had to be more carefully 
made than was practicable with an ordinary three-way cock. 
This brake valve was arranged so that in releasing the brakes, air was 
allowed to flow from the main reservoir on the engine into the train- 
pipe and auxiliary reservoirs. The engineer by moving the handle to 
the application position connected the trainpipe to the atmosphere 
through very carefully graduated openings and the pressure gauge 
connected to the trainpipe showed how much reduction was made, 
and indicated, therefore, the amount of air that would flow from the 
auxiliary reservoirs into the brake cylinders. As the discharge to the 
atmosphere from the trainpipe was slow, the pressure of the latter 
decreased throughout its entire length almost uniformally, and, as a con- 
sequence, the brakes were applied throughout the train with practically 
equal force and in about the same time. Thus the difficulty with 
straight air was overcome and the new conditions then existing were 
fully met. 

In the same year, 1872, the Smith vacuum brake appeared. This 
apparatus consisted of two collapsible cylinders on each vehicle, con- 
nected with two lines of trainpipe running throughout the train and 
connected between vehicles as in the compressed air brake. An 
'^ejector" was installed on the locomotive, by means of which the air 
in the trainpipes and brake cylinders was exhausted and the brakes 
applied through the contraction of the cylinders with which the brake 
levers were connected. The greater safety and efficiency of the auto- 



THE GROWTH 

OF 

CAR BRAKING 



Air Brake Tests ^^^^^^ 



made air brake was demonstrated so early 
that with a very few exceptions the plain 
vacuum brake soon passed out of service 
in the United States. For the same reasons the automatic vacuum, a 
later invention, was never adopted to any extent outside of England. 
The immense advantage to railway companies along the hne of 
higher speed, greater safety, and pronounced economy in the substitution 
of a reliable automatic power brake under the control of the engineer 
for the old hand brake was soon recognized and the work of making 
this change proceeded rapidly throughout the entire country. Natur- 
ally enough, the new conditions encountered brought to light new 
problems, the solution of which enlisted the best efforts of railway 
officials and brake manufacturers ahke. In many instances it was found 
that the only possible way to determine the questions involved with any 
degree of satisfaction was by means of practical tests made under such 
conditions as are found in actual service. 

It is the primary purpose of this publication to present in a compre- 
hensive way, and at the same time in condensed form, the data that 
has resulted from the most significant and valuable of these tests, with 
such comment as the wider experience of the day seems to justify. 



)0( 




\ 



O 

o 
u 
o 

< 



\\ 



w^ 



GALTON-WESTINGHOUSE TESTS. 

fk MONG the first and most important experiments of the char- 
/ % acter indicated were those made in England in 1878-1879 
A m. by Captain Douglas Galton and Mr. George Westinghouse, 
which had for their object the determination of the coefficient of friction 
between brake shoes and wheels and between wheels and rails, includ- 
ing the variation of this coefficient for different speeds and throughout 
different durations of brake application. The reports of these tests 
were made to the Institution of Mechanical Engineers of London in 
three papers, which are reproduced in the following pages with only 
such changes in the number of the illustrations as are unavoidable. In 
reprinting this most interesting contribution to the history of the 
development of power brakes for railway trains, the attention of the 
reader is called to the fact that the principles estabhshed by these 
tests made twenty-five years ago have never been superseded, but 
apply with equal force to present-day conditions. 

A short time previous to these experiments, a paper relating to 
brakes was read before the Institution of Mechanical Engineers, and 
during the discussion of this paper, Mr. Westinghouse called attention 
to the fact that, in testing the action of various kinds of brake shoes, 
he had observed a very marked difference in the friction of the shoes 
upon the wheels at high speeds and at low speeds. He believed that 
a determination of the facts was of great importance and volunteered to 
design and construct the necessary automatic recording apparatus and 
to carry out a system of experiments under the direction of any person 
who should be appointed by the President of the Society to supervise 
the tests and report to the Society. The Society immediately took 
advantage of this offer of Mr. Westinghouse and designated Captain 
Douglas Galton, who, on behalf of the Society, personally directed 
the experiments. The success of the project became assured when 
the London, Brighton «& South Coast Railway placed a locomotive 
and brake van at the disposal of Captain Galton and Mr. West- 
inghouse, and offered every facility for conducting the experiments ; to 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^^^ 



the great interest manifested by this rail- 
way, the valuable information secured 
from these experiments is largely due. 
It is not a little interesting to observe that the results obtained in 
these experiments, which were the first investigations of this character 
to be carried out upon any practical scale, may be considered among 
the most reliable data in existence upon this subject ; furthermore, 
subsequent investigations have tended to confirm the general character 
of the results, if not the entire accuracy of the data, thus presented. 



tk 



1 



ON THE EFFECT OF BRAKES UPON RAILWAY 
TRAINS. 



By Captain DOUGLAS GALTON, C. B., Hon. D.C.L., F.R.S. 



The following paper is an account of experiments upon the 
coefficient of friction between the brake-blocks and the wheels, and 
between the wheels and the rails, at different velocities, both when the 
wheels are revolving and when skidded. 

These experiments form the first instalment of a series which it is 
intended to make, in order to ascertain, 1st, the actual pressure w^hich 
it is necessary to exert on the wheels of a train in order to produce a 
maximum retardation at different velocities ; zd, the actual pressure 
exerted on the wheels with the several kinds of continuous brakes now 
in use ; 3d, the time required to bring the brake-blocks into operation 
in different parts of a train with the several kinds of continuous brakes ; 
4th, the retarding power of the different kinds of continuous brakes 
now in use on trains under similar conditions of equal weight and when 
running at the same speed. 

This paper includes the first series of experiments only. 

The author was enabled to make this series through the courtesy of 
the London, Brighton & South Coast Railway Company, and of 
their locomotive superintendent, Mr. Stroudley, who provided a van 
and other facilities for making the experiments ; and through the 
courtesy and assistance of Mr. Westinghouse, by whom the recording 
apparatus was designed. The author was assisted in making the 
experiments, and in their reduction, by Mr. Horace Darwin. 

The experiments described in this paper were made on the Brighton 
Railway, with a special van constructed for the purpose ; it was 
attached to an engine, and was run at various speeds, during which 
time various forces were measured by self-recording dynamometers. 
The principle of these dynamometers is that the force to be measured 
acts on a piston fitting in a cylinder full of water, and the pressure 
of the water is measured by a Richards indicator connected by a pipe 
to the cylinder; thus, as the drum of the indicator revolves, diagrams 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^"^''"^ 



are obtained giving the force acting on the 
piston. The advantages of this method 
are obvious, as the indicator can be 
placed at any convenient point, and the inertia of the w^ater tends to 
make the pencil keep a position corresponding to the mean force. 



rig.i 



PlaiL. 




Scale M th. 
Construction of Dynamometers. 



^""^''^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



The construction of the dynamometers 
is represented in Figs, i and 2. Each 
consists of a piston, and what answers to 
the cylinder, but would be better described as a cylindrical box with a 
ring fastened upon its upper edge. A is the rod by which the thrust to 
be measured is transmitted to the piston B. This piston merely consists 
of a cast-iron disc, having on one side a central cavity in which rests the 
rounded end of the rod A, and on the other side a central projection 
which acts as a guide. The ring C, resting on the edge of the cylin- 
drical box D and bolted to it, is of the same thickness as the piston, 
which fits within it, the ring and piston thus forming a cover to the box 
D. The piston fits so as to slide easily within the ring, with but little 
fi-iction ; and is made water-tight by placing below it a disc of india-rub- 
ber, which is fastened to the centre of the piston by a brass collar, and 
has its outer edge clamped in between the ring and the edge of the 
cylindrical box D. The dynamometer has thus a perfectly water-tight 
piston, which will move with very little friction ; and as its movement 
is very small, the disturbing effect of the india-rubber at its edge may 
be neglected ; consequently the forces acting on the piston through the 
rod A will be registered by the indicator by means of the pressure of 
the water. F is the pipe leading to the indicator. We will neglect 
the valve E for the present, and explain its use a little further on. 
Supposing the whole apparatus to be filled with water, and that a force 
were applied to the piston by the rod A, it would force some of the 
water out of the box D, through the pipe F, into the indicator cylinder. 
The area of the indicator piston is 0.5 square inch, and its maximum 
range 0.8 inch, therefore the quantity of water required to make a 
maximum movement of the pencil is 0.4 cubic inch ; and as the area of 
the piston B is 30 square inches, its movement would only be 0.013 or 
yi-g- inch ; which is such a small movement that the india-rubber will 
introduce no appreciable error. 

If the indicator piston did not leak, and if it were possible to keep 
exactly the right quantity of water in the apparatus, nothing more 
would be required to make it work properly ; but as this is evidently 
impossible, the self-acting supply valve E, opening outwards, becomes 



GALTON- 
WESTINGHOUSE 

TESTS 



Air Brake Tests ^''^''^ 



necessary. A small pipe G leads from an 
accumulator H, Fig. 3, which is loaded 
to a greater pressure than can ever arise in 
the box D ; the excess of pressure from the accumulator tends to close 
the valve E ; and there is also a spring w^hich forces the valve on to its 
seat. The valve is seated v^ith india-rubber, and is made perfectly 
w^ater-tight ; its spindle passes up so as very nearly to touch the brass 
collar on the inner side of the piston. Suppose the whole apparatus to 
be filled with water when there is no force acting on the piston ; then 
if a sufficient force is applied by the rod A, this will move the piston 
inwards so as to send some water into the indicator, and raise the pen- 
cil, and will also open the valve E ; and, as the pressure in the accu- 
mulator is in excess of that in the box D, water will enter the box, and 
will go on entering till the piston is raised again so as no longer to open 
the valve. Now, if the force on the piston be removed, the indicator 
spring will force the quantity of water received, which is less than 0.4 
cubic inch, back into the box D, and will thereby raise the piston, but 
through a space less than yL. inch ; and thus the piston will never move 
more than J^ inch above the position in which it touched the valve E. 
But if a smaller force be applied to the piston, as in practice, it will not 
be pushed in so far, unless sufficient leakage has meantime taken place ; 
in that case the piston will move inwards through its full distance, and 
will then open the valve. Thus the valve always keeps the right 
quantity of water in the apparatus to make it work properly, by 
occasionally opening and letting in enough water to make up for 
leakage. 

In Figs. 3 and 4 is shown in elevation and plan the general 
arrangement of the apparatus in the special brake-van built by the 
London, Brighton & South Coast Railway Company for these 
experiments. To this van the Westinghouse automatic brake was 
applied, having four dynamometers attached to it, like the one 
described. The dynamometers Nos. i and 2, situated as shown in 
Figs. 3 and 4, measure the retarding force which the friction of the 
brake-blocks exerts on the wheels ; No. 3 measures the force with 
which the blocks press against the wheels ; No. 4, the force required 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^""^''^ 



to drag the van. The arrangement of 
the levers for applying the brake is not 
the same as that used on the ordinary 
rolling stock of the Brighton Railway, but has been slightly modified 
by Mr. Westinghouse in order to make the pressure equal on both sides 
of the w^heels, and to provide for the application of the dynamometers. 
M is the cylinder belonging to the Westinghouse brake apparatus ; 
into this the compressed air flows from the reservoir N when the brake 
is apphed, and forces the two pistons apart, thus moving the two rods 
P P outwards, and by means of the levers pressing the brake-blocks 
against the wheels. It is evident from the arrangement here shown 
that the pressure must be equal on each side of the wheels ; and that 
the pressure on dynamometer No. 3 must be equal to the thrust on 
the rod P, and hence proportional to the pressure on the wheels. 
The lever Q, pivoted at its center, will evidently tend to turn with 
a moment equal to the retarding moment exerted by the friction of 
the brake-blocks on the wheels ; and hence dynamometers Nos. i 
and 2 will register forces proportional to this moment. The brake 
could be apphed to all the wheels of the van, but during the experi- 
ments it was only applied to the pair of wheels to the levers of which 
the dynamometers Nos. 1,2, and 3 were attached. Dynamometer 
No. 4 is connected to the drawbar by a lever, as shown in the plan. 
Fig. 4, and thus registers the force required to draw the van. A 
self-recording speed-indicator was used, designed by Mr. Westing- 
house. This instrument has been repeatedly tested, and was used 
at the brake trials on the North British Railway, and on the Ger- 
man State Railway. It consists of a small dynamometer made on the 
same principle as that just described ; it measures the centrifugal force 
of two weights, which are made to revolve by a strap from a pulley 
on a shaft driven by friction-gear from the pair of wheels to which 
the brake was applied ; a Richards indicator is used, as with the 
other dynamometers. As the centrifugal force varies as the square of 
the velocity, the speed is got by taking the square root of the ordinate 
at any point of the indicator diagram. 

The diagrams from the speed indicator show the speed of the pair of 



I 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests 




wheels to which the brake was appHed, 
and therefore the velocity of the train at 
the moment of applying the brake and sub- 
sequently, provided there is no slipping. Any variation in the speed 
diagram is due to the wheels slipping, and shows to what extent and in 
what way the brake stops the wheels. Two of Mr. Stroudley's speed 
indicators were fixed side by side in the van ; one attached to the axle 
belonging to the braked wheels, the other to the axle which was run- 
ning free. The difference of these indicators showed if slipping took 
place. They did not record any diagrams, but were read by means of 
a Bourdon gauge attached to them, with the face divided in such a way 
that the hand shows the speed in miles per hour. A similar gauge was 
attached, for convenience, to the Westinghouse speed indicator de- 
scribed above. 

The indicators were all placed on a table T in the center of the van, 
as shown in Figs. 3 and 4 ; and their drums were made to revolve by 
the cords being wound up on pulleys on the shaft S, which is turned 
at a uniform rate by a water clock U. This clock merely consists of 
a plunger shding in a cylinder through a water-tight packing, and loaded 
with a heavy weight ; it is wound up by connecting it with the ac- 
cumulator H, and at the beginning of each experiment a small cock is 
opened, which allows the water to run out and the weight to fall, 
thereby turning the indicators round at an ascertained uniform speed. 
Thus while the ordinates of the diagrams taken from these several 
indicators show the various forces, the abscissas show the time occupied 
in the experiments. 

In these experiments the tires were of steel, and the brake-blocks 
of cast-iron. 

The difficulties attendant upon the preparation and adjustment of this 
delicate apparatus consumed so much more time than had been antici- 
pated, that it was only on the 27th, 28th, and 29th of May that a 
series of experiments could be made. These took place in the vicinity 
of Brighton. The first day was dry ; the second stormy ; the third 
fine, with showers. 

Numerous diagrams were taken by the apparatus, which have re- 



II 



^''^'^' Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



quired very careful reduction. Unfortu- 
nately the date at which it was necessary 
to send in the paper to the Institution 
has not afforded time for a complete collation of the results ; the author 
therefore submits this as a preliminary paper ; and limits himself to 
exhibiting in Figs. 5 to 1 3 a few of the indicator diagrams which 
were taken, and which illustrate the more striking results. 

In these diagrams, the line P P represents the Pressure applied to the 
brake-blocks in lbs. ; its ordinates multiplied by 240 give the total pres- 
sure in lbs., collectively exerted upon the four brake-blocks of the 
braked pair of wheels. The line F^ F^ represents the corresponding 
Friction between the brake-blocks and the wheels, as measured by 
dynamometer No. i ; its ordinates multiplied by 45 give the total 
friction in lbs., collectively produced between the two brake-blocks, 
to which No. I was attached, and the wheel. The line F^ F- 
represents the same for dynamometer No. 2. The line T T repre- 
sents the Traction upon the draw-bar in lbs. ; its ordinates multiplied 
by 60 give the absolute strain upon the draw-bar in lbs. The line 
S S represents the linear speed of the circumference of the braked 
wheels in miles per hour, which, when there is no slipping, is equal 
to the velocity of the train. The length of each diagram shows the 
duration of the experiments in seconds, according to the scale marked 
along the base line. 



Miles 


Fig. 5 Experiment No. 1 

. ' s 


Lbs. 
p. sq. in. 
50-1 


-30 Y" 
- 1/ 

- " ! 


I7'^''-^- .^--^.L A 

v\. 10- 





5 10 15 


20 Sec. 



No. I. 
Fig. 5. (Exp. I. 29th May.) — In this case the speed re- 
mained nearly constant, varying from 41 miles per hour at the 
beginning to 40 miles per hour at the end. 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^"^'^^ 



The compressed air was allowed to 

escape from the brake-cylinder through a 

small aperture, and thus the pressure 

between the blocks and the wheels diminished, as shown by line P P. 

The line F F shows that the friction between the brake-blocks and 

the wheels diminished more rapidly than the pressure. 

The speed indicated by the rotation of the wheels to which the 
brakes were applied was the same as that of the wheels running free : 
as shown by the Stroudley indicators. 



Fig. 6 






Experiment !No. 2 



Lbs. 
p. sq. in. 
100 






1! 

Miles j ! 
per liour I j 
.-aft I j 

!i 



y \ 

i ^^ 
i 



10 

^0- 



\v.^.^.^..^- ^>^j[l. 



\ 
\ 



T 1 1 r- 



No. 2. 

Fig. 6. (Exp. II. 27th May.) — This experiment was com- 
menced when the van was moving at a speed of 25 miles an hour. 
The application of the brake slackened the speed to 20 miles an hour 
in ten seconds, when the wheels skidded, as shown by line S S ; and 
the experiment terminated in 22 seconds, when the speed had been 
reduced to i 7 miles an hour. 

In this case the line S S shows no diminution in the speed of rotation 
of the wheels below the speed due to the velocity of the train, until 
the skidding took place. In the 10 seconds which elapsed from the 
time when the brakes were fully on till the wheels skidded, the speed 
of the train was reduced from 25 to 20 miles an hour, as shown by 
the line S S j whereas in the period of 1 1 seconds which elapsed 



^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



between the skidding of the wheels and 
the cessation of the experiment the train' s 
velocity was only reduced from 20 miles 
to 17 miles per hour, as shown by the Stroudley indicators. The 
skidding was only momentary, the w^heels beginning to revolve again 
almost instantly ; but the grip of the brake-blocks w^as then almost en- 
tirely on one wheel, as shown by the wide divergence between the lines 
pi pi and p2 F-; even in the case of the higher line the friction 
was much less than before the skidding ; so that the total retarding 
eifect on the train was greatly diminished. 



Fig. 7 . Experiment No. 3 



Lbs. 
p. sq. in. 





'■\ 








\ 






f' 


.1 






N ^"^ 


■^\ 






vJ 


■\ 






-.-'-7-1-,. 


T 


i\ 




/ ^\ 




^1 


^^»' 


^>. - 


/ 


/2y. 



No. 3. 

Pig. 7. (Exp. 24. 28th May.) — In this experiment the velocity 
of the train was 2 i miles an hour when the brakes w^ere applied to the 
wheels, and was reduced by the action of the brakes to 18 miles, 
when the wheels immediately skidded. 

The line P P shows that the coefficient of friction between the 
brake-blocks and the wheels gradually increased as the speed diminished, 
until the skidding point was reached ; and line T T shows that the 
tractive force exerted on the draw-bar was suddenly greatly diminished 
after the skidding took place. 

No. 4. 

Pig. 8. (Exp. I 5. 28th May.) — In this case the brake-van was de- 
tached from the engine by means of a slip coupling, w^hen traveling at a 
speed of 40 miles an hour. The pressure of air in the brake-cylinder. 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^"^'^4 



and consequently the pressure on the brake- 
blocks, remained nearly constant during 
the experiment, as shown by line P P. 
The pressure being greater than that required by the coefficient of 
friction between the brake-blocks and wheels corresponding to the 

i ! 
/ii! 



Lbs. 

p. sq. in. 

100 



Fig. 8 



Experiment No. 4 



Miles 
per hour 
45 







! il 



^J-'' 



V — y 



/'^.y / 

.^""'i'' 



il 






velocity, the friction increased so rapidly as to cause the wheels to skid 
immediately, as shown by the line S S. 

After the skidding, the friction at once increased rapidly, as shown 
by F F ; but rose again as the train's velocity diminished, and attained 
.its maximum when the train came to rest, which occurred in many jerks 



in 1 2 i^ seconds. 



No. 5. 

Fig. 9. (Exp. 16. 28th May.) — In this case also the brake- 
van was detached from the engine by means of a slip coupling, when 
travelling at a speed of 46 miles per hour. 

The pressure of the air in the brake-cylinder was less than in the 
preceding case, and it was gradually diminished during the experiment ; 
consequently the force with which the blocks pressed on the wheels 
diminished to the same slight extent, as shown by P P. 

At first the friction between the brake-blocks and wheels also dimin- 
ished very slightly ; but when the velocity of the van had greatly 



^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



decreased, as shown by S S, the friction, 
as shown by F F, increased rapidly. The 
van came to rest in 1 2 seconds, with- 
out any jerk, before this friction had risen to a point sufficiently 
high to produce skidding. 

These two diagrams. Figs. 8 and 9, afford a comparison of a stop 

Experiment ^o. 5 



Miles 
per boMr 




with skidding and one without skidding. The latter stop was effected, 
with a uniform motion without jerks, from a speed of 46 miles an 
hour, in i 2 seconds ; while the former required 1 2 ^ seconds to stop 
from a speed of 40 miles an hour, with a series of unpleasant jerks. 



Lbs. p. sq. in. 
100 



Fig. 10 




No. 6. 
Fig. 10. (Exp. 3. 28th May.) — In this experiment the train's 
velocity was uniform throughout at 441^ miles an hour. The pressure 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^""^'^^ 



applied to the brake-blocks sufficed to 
skid the wheels at once, as shown by S S. 
The line F F shows that the coefficient 
of friction between the brake-blocks and the wheels decreased immedi- 
ately after the skidding, and only rose at the end of the experiment. 

Line T T shows that the tractive force on the draw-bar increased 
with the act of skidding, but largely decreased as soon as the skidding 
was effected. 

Fig. 11 Experiment ^o. 7 



No. 7. 

Fig. 1 1 . (Ex. 2 1 . 28th May. ) — In this experiment the speed was 
45 miles an hour at the beginning, and decreased to 42 ^ miles at the end. 

The pressure was slightly decreased during the experiment ; it did 
not suffice to skid the wheels ; and the wheels with brakes and those 
without brakes revolved at the same rate, as shown by the Stroudley 
indicators. 

The tractive force on the draw-bar, shown by T T, follows a 
nearly uniform line. 

A comparison between this diagram. Fig. 1 1 , and the preceding 
one. Fig. 10, shows that, although the pressure on the brake-blocks in 
the former case, in which the wheels were skidded, was greater than 
in this case, where the wheels were not skidded, yet the practical 
effect of the brakes, as shown by the tractive force on the draw-bar, 
was much greater with the wheels braked but not skidded (Fig. 11), 
than with the skidded wheels (Fig. ro). 



^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



No. 8. 

Fig, 12. (Exp. 9. 29th May.) — 
In this experiment the van and the 
engine were brought to rest by means of the brake from a speed of 
40 miles per hour. 

The wheels skidded very quickly after the brake was applied, 
as shown by the line S ; the retarding force, shown by F F, rose 




Xbs. 
p. sq. in. 



Fig, 13 Experiment No. 8 



•B 

Miles **"*■•——•.•«... 

per hour **""""——-.—. ., 



../'^. ..- 






t—^-/-W-4.' 



/ 



y 



!\ 



T^^ 



greatly at the moment of skidding, and then fell considerably below 
the original amount. The wheels remained skidded to the end of the 
experiment. 

The diagram shows an increase in the coefficient of friction, 
measured by the rise in the friction line F F, and fall in the pressure 
line P P, as the train's velocity diminished ; this increase was slight at 
first, but more rapid as the velocity became reduced, and was very 
great at the moment of stopping. 

No. 9. 

Fig. 13. (Exp. 3. 29th May.) — In this experiment the van 
and the engine were brought to rest from 39 miles an hour by means 
of the brakes upon both. 

The compressed air in the brake-cylinder was allowed to escape 
through a small aperture after the brake was applied ; and thus its 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^""^'^^ 

pressure,, and consequently the force 
with which the blocks pressed against 
the wheels, diminished during the ex- 
periment, as shown by P P. 

The line F F shows that the retarding force due to the pressure of 
the brake-blocks on the wheels at first diminished, until the reduction 
of velocity, shown by S, reached the point where the increase in 
the coefficient of friction was sufficient to overcome the effect of the 
diminished pressure apphed to the brake-blocks. From this point the 
retarding effect of the brakes increased rapidly, and before long the 
wheels were skidded. Up to this point the two pairs of wheels of 

Lbs. p. sq. In. 
\\ 

Fig< 13 Experiment No* 9 




the van, to one of which brakes were apphed whilst the other was 
running freely, had revolved approximately at the same rate, as shown 
by Mr. Stroudley's speed indicators. At the moment of skidding the 
friction curve F F rose in a nearly vertical line, thus showing that the 
coefficient of friction became very great as the wheels came to rest ; 
and the time during which the wheels were partly rotating and partly 
slipping was almost inappreciable. Immediately after this rise the 
curve F F fell to a point far below its former level, thus showing a 
great diminution in the retarding effect of the brakes as soon as the 
wheels were skidded. After this point the curve rose again while the 
velocity continued to decrease ; and thus showed that the coefficient of 
friction between the rails and the skidded wheels increased as the 
velocity of the train diminished. At the moment when the van came 



^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



to rest the coefficient of friction became 

very great, as shown by the final rise in 

F F. The traction Une T T varies 

greatly, according to the working of the brakes upon the engine and 

van respectively. 

It is unnecessary in this preliminary paper to give the particulars of 
the reduction of the diagrams ; but the principal results shown by them 
may be summed up as follows : — 

1 . The appHcation of brakes to the wheels, when skidding is not 
produced, does not appear to retard the rapidity of rotation of the 
wheels. 

2. When the rotation of the wheels falls below that due to the 
speed at which the train is moving, skidding appears to follow 
immediately. 

3. The resistance which results from the appHcation of brakes with- 
out skidding is greater than that caused by skidded wheels. 

4. Just at the moment of skidding, the retarding force increases to an 
amount much beyond that which prevailed before the skidding toolc 
place ; but immediately after the complete skidding has taken place, 
the retarding force fall down again to much below what it was before 
the skidding. 

5 . The pressure required to skid the wheel is much higher than that 
required to hold them skidded ; and appears to bear a relation to the 
weight on the wheels themselves, as well as to their adhesion and 
velocity. 

It would seem that the great increase in the frictional resistance of 
the blocks on the wheels just before and at the moment of skidding, due 
to the increase in the coefficient of friction when the relative motion of 
the blocks and the wheels becomes small, is what destroys the rotating 
momentum of the wheels so quickly. 

With constant pressures, the friction between the blocks and the 
wheels, and consequently the retarding force, increases as the velocity 
decreases. 

In order to obtain the maximum retarding power on a train, the 
wheels ought never to skid ; but the pressure of the brake-blocks on the 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^^^ 



wheels ought just to stop short of the 
skidding point. In order that this may 
be the case, the pressure between the 
blocks and the wheels ought to be very great when the brakes are 
first applied, and ought gradually to diminish until the train comes to 
rest. 

There are other points of interest indicated by the diagrams which 
require further elucidation ; among which may be mentioned the 
question whether the coefficient of friction diminishes when the pressure 
increases and the velocity remains constant. Another question is as to 
the practical effect on the wheels themselves resulting from the greater 
amount of work done by retarding the wheels without skidding, as 
compared with the effect of skidding. 

The general conclusion which would appear to follow from the 
results of these preliminary experiments is that none of the hand brakes, 
and only some of the continuous brakes now in use, have been designed 
with a clear knowledge of the most essential conditions required in a 
perfect brake. 

Experiments connected with the action of brakes on railway trains 
require very delicate apparatus ; and the author in conclusion wishes to 
explain that the credit of the design of the apparatus used in these 
experiments, and of the successful manner in which the apparatus was 
applied, belongs entirely to Mr. Westinghouse. The efficiency of the 
arrangements for making the experiments which contributed to the 
successful results obtained is due to the London, Brighton & South 
Coast Railway Company, as represented by their locomotive engineer, 
Mr. Stroudley, who gave much personal attention to the work, and by 
Mr. Knight, the general manager, who afforded every facility for the 
use of the line. 



ON THE EFFECT OF BRAKES UPON RAILWAY TRAINS. 

( Second Paper, ) 



By Captain DOUGLAS GALTON, C. B., Hon. D.C.L., F.R.S., of London. 



The experiments which the author brought to the notice of the 
Institution at the Paris meeting have since been continued, and the 
results then obtained have been more completely investigated. 

The apparatus used v^as substantially the same as was described in 
the first paper. But for the new experiments, it has been somewhat 
altered by a rearrangement of the levers. The altered arrangement is 
shown in Figs. 14 and 15. In the first experiments the friction of 
each pair of brake-blocks upon the wheel was recorded on a separate 
diagram. By the rearrangement the levers from all the brake-blocks 
act on one dynamometer, and the friction of all the four brake-blocks 
applied to the pair of braked wheels is recorded on one diagram. The 
description of the manner in which these levers act, given in the first 
paper, applies generally to the altered arrangement. An addition was 
also made to the apparatus, for the purpose of obtaining the proportion 
of the weight of the van which rested on the braked wheels. To effect 
this, a dynamometer (No. 2 ), of similar construction to the others 
already described, was fixed to levers L L, as shown in Figs. 14 and 
I 5 , these levers being connected with the ends of the springs which 
support the body of the van above the unbraked wheels. From the 
diagrams furnished by the indicator for this dynamometer, the propor- 
tion of the weight of the body of the van resting on this pair of wheels 
was obtained. 

The weight of the body of the van with the apparatus, etc., when 
stationary, was found to be as follows : — 

On wheels not braked 8,764 lbs. 

On braked wheels 9j436 lbs. 

Total 18,200 lbs. 

To this had to be added the weight of the persons in the van, and 
that of the wheels, axles, axle-boxes, and springs. The former was 





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GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^''^^^^ 



assumed at 1 60 lbs. per person ; an ex- 
periment made by weighing thirteen per- 
sons, who had traveled in the van on one 
of the days of the experiments, having given an average weight of i 5 9 
lbs. per person. The latter was obtained as nearly as possible from the 
records of the locomotive department of the Brighton Railway, and 
formed a constant quantity, one-half of which, with the allowance for 
the number of persons in the van, was added to the difference between 
the weight shown by the diagrams and the total weight of the body of 
the van, to obtain the weight on the braked wheels. This weight 
varied at almost every moment during the experiments, and the actual 
weight at the moment has in all cases been taken for calculating the 
adhesion.^ 

Preliminary Observations on the Experiments, — The author would 
in the first place observe that most of the conclusions given in the first 
paper will be found to be generally borne out by a further study of the 
diagrams ; but some modification is required in the opinion expressed 
that, when the friction of the brake-blocks is sufiicient to check the 

"^ The mode of action of the dynamometers used for measuring the various forces was 
described in the first paper 5 but as many questions have been asked of the author about 
the action of the supply valve E ( Fig. 4 ) , the following remarks are here added 
as a note. 

In order to make the action of the valve more clear, let it be supposed that there is 
a constant force, such as a weight, acting on the piston B B, and that the whole appar- 
atus is full of water. As the water slowly leaks past the piston of the indicator, the 
piston B B will slowly descend until the brass collar touches the top of the valve 
spindle. It will take some force to open the valve, on account of the excess pressure 
of water on its other side, and also on account of the spring which forces it on its seat ; 
and this will introduce a small error in the reading of the indicator, as the whole 
weight will not be supported by the pressure of the water, and consequently the pres- 
sure will fall and the indicator pencil will stand too low. 

As the leakage continues, the brass collar will force open the valve, and it will open 
it just so much as to allow the same quantity of water to enter as leaks past the indi- 
cator piston 5 for if more comes in than leaks out, the piston B B will be raised, and 
the valve will close slightly and thus diminish the quantity of water which enters j and 
if less comes in, the opposite takes place. In passing through the small opening of the 
valve the water is wire-drawn, and its excess pressure destroyed. 



^"^^^-^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



rotation of the wheel, the rotation is 

immediately stopped altogether. On the 

contrary, a closer examination of the 

diagrams shows that in every case where the wheels become locked 

and slide on the rails, there occurs, just before this takes place, an 

appreciable interval of time during w^hich the speed of rotation is 

gradually, though rapidly, diminished. 

General Description of the Experiments, — The brake-blocks were 
applied to both sides of the wheels ; that is to say, there were four 
brake-blocks to each pair o1 wheels. This arrangement prevents a strain 
being brought upon the axle. The blocks were made of cast-iron — 
wooden blocks being too soft, and wrought-iron blocks proving irregular 
in their action, apparently from a change in condition, owing to the 
high temperature evolved by friction. It would indeed seem probable 
that wrought-iron as well as steel blocks would prove injurious to the 
tires. 

The experiments on the Brighton Railway, which were made with 
the experimental van and an^engine, have been supplemented by some 
fiirther experiments made on the North Eastern Railway with a train 
of twelve vehicles fitted with the Westinghouse brake and a similar train 
fitted with the Smith-Hardy vacuum brake. 

The experiments on the Brighton Railway may be divided into two 
classes : ( i ) those made whilst the speed of the engine was kept up at 
an ascertained rate ; ( 2 ) those made by slipping the van when the 
required speed had been obtained, and allowing the van to come to rest 
by the application of the brakes. In the first class of experiments the 
recording apparatus was set in motion by hand at a convenient time 
before the brake was appHed ; in the second class the recording 
apparatus was set in motion by the automatic application of the brake at 
the moment of separation from the engine. 

The general action of railway brakes may be thus described : When 
a train is moving at a given velocity, the adhesion of the wheels on the 
rails causes them to revolve ; every point on the surface of the tire 
moves round at the same rate as that at which the train itself is moving 
forward ; but every such point, in relation to the forward movement of 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^^^ 



the train, comes successively to rest at the 
moment when it comes in contact with the 
rail. Now, when the brake is applied 
with a slight pressure only, the wheel continues to move round at the 
same rate as the train is moving, but it moves with more difficulty, and 
this increased difficulty in moving is shown either by an increase in the 
tractive force required to keep up the forward motion, or, in cases where 
the accelerating force is not kept up, by the tendency of the moving 
mass to come to rest in a shorter time than would otherwise be the 
case. But if the pressure with which the brake is applied be increased, 
a point is reached when the friction between the brake-block and the 
wheel first approaches, then equals and finally exceeds the adhesion of 
the wheel on the rail, which adhesion corresponds with the static 
friction between the surfaces, because the part of the tire in momentary 
contact with the rail during its rotation, is for that moment at rest in 
relation to the forward movement of the train. When this happens, 
the wheel first begins to revolve more slowly, and then ceases to revolve 
and slides along the rail, or, as it is usually termed, is skidded. In this 
case the retardation is no longer due to the pressure upon the brake- 
block and consequent friction between the brake-block and the tire of 
the wheel ; but the vehicle is transformed for the time from a vehicle 
on wheels into a sledge, and the retardation due to the brakes is thus 
the excess of resistance which is produced by making the vehicle slide 
along the rails, over that produced by making the vehicle move forward 
on wheels revolving fi-eely. 

It is therefore necessary to consider the experiments under these two 
different conditions of retardation, and we arrive at the two following 
conclusions : — 

(A) So long as the wheels continue to revolve, the measure of 
retardation is the friction between the brake-blocks and the wheels, and 
this is represented by : — 

The coefficient of friction between the brake-blocks and the 
wheels X the pressure applied to force the blocks against 
the wheels. 

(B) As soon as the wheel begins to slide on the rail, the measure of 













Lbs. p. Kq. in. 




/• 


P 








/ 




Fig. 16 Experiment T^o. 10 


140- 






J 

r 




I'niform Speed of Braked Wheels, 


130- 


Miles 
per hour 




/ 

1 




aud rniform Pressure on Brake -Blocks. 
Gradient rising 1 in 176. 


120- 
110- 


-60 








100- 




s 


i 






^..j^.^ SO- 
SO - 
70- 


-50 




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^"**- — -^JC 






-40 




'/' 






50- 


-30 


( 


/ 

\ 


,..., 




40- 
30- 






"" F 


-20 _jr 

-10 

'^O 1 — r 


/! 


y'F 

1 i ' 1(1 


1 — r- 


-T — 1 — 1 — \ i — 1 — 1 — 1 — 1 i — 1 — 1 1 — 1 — 1 — 1 — r 


20- 

10- 

1 1 1 1 



Miles ( 

per hour; T__ 

.1 



20 j; 



Fig. 17 



Experiment ^o. 11 



Uniform Speed of 3raked Wheels, 

aud Vniform Pressure on Brake-Blocks. 

Gradient level. 



; . Lbs. 60 

\ 



z — r"s~ 

N \ 

W 

■■■■'■ -..^^ 

■••..\ 







20 25 30 Sec. 

"\ /^' ^ '*\ Lbs. 90-\ 

\ I \ soH 

Experiment ^o. 12 \ j 



\ I 



Uniform Speed of Braked AVheels, 

and Varying Pressure on Brake-Blocks. 

Gradient rising 1 in 220. 



P Pressure on Brake-Blocks, in lbs. T Traction upon Draw-Bar, in IhS. 

F Friction hetvveen Brake-Blocks and Wheels. S Speed of Braked Wheels, miles p. hour. 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^^^ 



retardation is the friction between the 
wheel and the rail (which is equal to 
the strain exerted by the brake-blocks 
to hold the wheels in their fixed position), and this is represented 

by:- 

The coefficient of friction between the rails and the wheels X the 
weight upon the wheels. 
In considering these experiments, it will therefore be convenient to 
class the results obtained under the following heads : — 

1. The coefficient of frictioii between the brake-blocks and the 

wheels, 

2. The coefficient of friction between the wheels and the rails, 

3 . The general effect of the application of the brakes in retard- 

ing the train, as shown by the strain on the draw-bar, 

4. The proportion which the pressure applied to the brake-blocks 

should bear to the weight on the wheels at different 
velocities, 

5. The effect of the time expended in bringing the pressure to 

bear on the wheels, 
I. Coefficient of friction between the brake-blocks and the wheels. 
The diagrams^ shown in Figs. 16 to 18 will conveniently illustrate 
this question. During each of these experiments the velocity of the 
braked wheels was uniform, as shown by the line S S. In Fig. 16 the 
pressure on the brake-blocks was also uniform, as shown by the line 
P P. In Fig. 1 8 the pressure P was made to vary. 

It appears from Fig. 16, where the pressure and velocity were 
practically uniform, that the friction diminishes as the time of application 
of the brakes continues. This is shown by the fall in the friction line F F. 

* The multipliers required in the present series of diagrams for reducing the ordi- 

nates to actual lbs, of force are somewhat different from those in the former series (see 

p. 31). They are here as follows : — 

. f6o before skidding. 

• ( total friction on blocks ) < 

' (67.5 during do. 

(total pressure on blocks) 240. 

(total traction on draw -bar) 30. 

(speed of braked wheels) — to scale. 



Line F F, 


No. 


I. E 


)ynamoi 


Line P P, 


No. 


3- 


do. 


Line T T 


No. 


4- 


do. 


Line S S, 


No. 


5- 


do. 



^^^^^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



It appears from Fig. 1 8, that the friction 
varies with the pressure, the friction line 
F F following the rise and fall of the press- 
ure line P P ; and it appears by comparing Fig. i6, where the velocity 
was 55 miles an hour, and Fig. 17, where the velocity was 40 miles an 
hour, with Fig. 20, where the velocity was only i 5 miles an hour, that 
the proportion of friction to pressure was greater at the lower than at 
the higher velocity. This latter fact is further shown in Fig. 1 9, where 
the experiment commenced at a speed of 52 miles an hour, and ended 
with the train coming to rest. In this case the effect of time on the 
application of the brakes came into play at first, and the friction became 
somewhat reduced ; but when the velocity had seriously diminished, 
the friction rapidly increased until it nearly approached the value of 
static friction. The proportion which exists between friction and 
pressure is the coefficient of friction, and it thus appears that the coeffi- 
cient of friction increases as the velocity dimi?nshes ; and diminishes y 
at any rate when the surfaces are steel and cast-iron, as the time 
increases during which the pressure has been applied. 

Some special experiments were made with blocks of small area. 
The brake-blocks generally used in these experiments were 1 2 inches 
long by 3 inches wide, giving a surface of 3 6 square inches ; the small 
brake-blocks were made so as to afford a surface of pressure against the 
wheel of only one-third of this amount, or 1 2 square inches, thus 
making the pressure per square inch three times as great as before. 
The diminution of surface was obtained by casting projections upon the 
face of the block. The author is not prepared to say that any greater 
coefficient of friction was obtained by the extra pressure per square 
inch, although in one of the experiments. Fig. 21, at a velocity of 60 
miles an hour, the rotation of the wheels was arrested by these blocks, 
whilst this effect had not been produced at that speed in other experi- 
ments. The experiments on this form of block were stopped because 
the blocks were entirely worn down in the course of about twelve 
experiments. 

Mr. Rennie showed^ that high pressure per square inch produced a 
* Phil. Trans, for 1829, p. 159. 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests £f£l£f 



greater coefficient of friction between sur- 
faces either moving very slowly or nearly 
at rest ; but it must be borne in mind 
that the author' s experiments were made with high velocities, whereby ' 
a serious element of disturbance is introduced, viz., the grinding away 
of the surface ; and it is therefore probable that the increase in the 
coefficient of friction due to increased pressure may have been neutral- 
ised by the lubricating effect of the fine particles ground off the 
surfaces. 

While the author refrains from expressing any certain opinion as to 
the relation which the coefficient of friction bears to pressure, so far as 
these experiments are concerned it is quite clear that in proportion as 
the pressure is increased or diminished so will the actual friction 
obtained be increased or diminished. When the friction which exists 
between the brake-blocks and the wheel thus reaches a certain point, 
the wheel ceases to rotate and becomes fixed. This point is reached 
when the frictional resistance of the blocks exceeds the adhesion 
between the wheel and the rail if the speed is kept up ; or, if the 
speed is slackening, when it exceeds the adhesion between the wheel 
and the rail, plus the effort required to retard the rotation of the wheel 
equally with the retardation of the train ; and the excess of resistance 
then acts as an unbalanced force, tending to destroy the momentum of 
the wheel. As far as can be judged from the experiments, it would 
seem that, whether the speed be high or low, nearly the same absolute 
amount of frictional resistance is required to skid the wheel, other 
things being equal ; but that the time during which the rotation of the 
wheel is slackening, before it is completely stopped, varies with the 
speed. Thus it would appear from a comparison of Fig. 20 with Fig. 
2 1 , that whilst at 1 5 miles an hour the wheel skidded in about ^ 
second, at 60 miles an hour it required about 3 seconds to skid the 
wheel. 

The amount of frictional resistance which determines the point at 
which the rotation of the wheels is checked varies, it is true, in the 
different experiments. The ratio which it bears to the weight upon 
the braked wheels is in some cases as low as .19; and in some cases* 



Miles 
per hour 



r55 
-50 


N 


Fig. 19 Experiment No. 13 

\. Decreasing Speed of Braked Wheels. 










;^V rniform Pressure on Brake-Blocks. 






■40 

-30 

-20 
10 


/" 


^S. F/\ 


— P 


Lbs. 
p. 8q. in. 
40- 

30- 

20- 

10- 

0- 


"" "^^\^ .••••*■* ^'^""' 


If 

r-n- 


T — 1 — 1 — 1 — 1 — I — 1 — 1 — 1 — 1 — 1 — 1 — 1 — I — 1 T 1 — r— r^ 



Fig. 20 ,, Experiment No. 14 




Lbs. 
p. sq. in. 


Miles /"t 1 .: 






60- 


per hoar / • r:" ^i 


^^/i 








^11 ;i 

1 .^;. p 1 1 

1 ;: : ">*. i I 


50- 
40- 


/V..P..--" • il ii 

so / / ■' -■ --i: 


m- 


-fi 


30- 


■ / \ ......i! 


!.// :> 


li 


20- 


- ^ s ■■■■ '■ v.. 




..... y 
1^ 


^l...i»- 


^0 — 1 — I — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1 1 1 -I — 


T 1 1 1 1 1 1 1 


-I — 1 — 


^^^^^ 0- 



Fig. 21 Experiment No* 15 

Brake -Blocks of small area. 




GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^''^'^' 



as high as .35 or even somewhat more, 
the average being about . 2 5 of the w^eight 
on the v^heels. But it clearly represents 
simply the adhesion betv^een the w^heel and the rail, and varies only 
with this, and not with the speed. Thus in Fig. 21, where the 
velocity was 60 miles an hour, the amount of actual frictional resist- 
ance which checked the rotation of the wheels was about 2,000 lbs., 
exhibiting an adhesion of about 19.1 per cent. Again, in Fig. 20, 
where the velocity was i 5 miles an hour, the actual amount of friction 
appears to have been about 2,160 lbs., exhibiting an adhesion of about 
19.6 per cent.^ As these two values are so nearly equivalent, it 
would thus appear that the effort retarding rotation is much the same 
at all speeds ; and therefore that the point at which the retardation of 
the rotation of the wheels commences does not vary with the momen- 
tum of the wheels, but depends entirely upon the adhesion between 
the wheel and the rail. 

It will be observed in Figs. 20 and 21, where the wheel was 
skidded, while the train went on, as well as in Fig. 19, in which the 
experiment commenced at a high velocity and ended with the stopping 
of the train, that just before rest, at the moment when the rotation of 
the wheel was stopped, a considerable increase in the amount of fric- 
tion took place. At this point the coefficient of friction will be found 
to correspond with the coefficient which has been noted by former 
observers as that of static friction, or of friction between surfaces mov- 
ing at very slow velocities. The sudden jump in the diagrams shows 
the sudden change from the one coefficient of friction to the other, at 
the moment of the wheels ceasing to rotate. In some instances the 
. friction thus developed amounted to .30 and even .325 of the pressure, 
which is about equivalent to the coefficient of static friction between 
steel and cast-iron, as given in Rennie's experiments. 

It has been shown above that, whether the velocity be high or low, 
the period at which the rotation of the wheel is stopped, so that it 
slides on the rail, depends upon the amount of friction between the 

^ In this and other cases the diagrams exhibited are merely specimens of a very large 
number in the author's possession, all leading to the same conclusion. 



^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



brake-block and the wheel, the weight 
upon the wheel, and the condition of the 
rails, which governs the adhesion between 
the wheel and the rail. Therefore, with the same weight on the 
wheels, and the rails in a similar condition, the same amount of brake 
friction will stop the rotation of the wheels whatever be the speed. 
The manner in which speed affects this question is due to the fact 
that in order to obtain the same absolute amount of frictional resistance 
at a high speed as at a low speed a greater pressure is required. 

For instance, selecting at random two experiments (No. i6 and 13, 
of the 2 2d July), in the first, with a speed of about 16 miles an hour, 
a pressure of 8,169 lbs. applied to the brake-blocks produced a friction 
of 1,560 lbs; whilst in the second, with a speed of about 50 miles per 
hour, a pressure of 13,900 lbs. applied to the brake-blocks produced a 
friction of only 1,400 lbs. 

There is much difficulty, however, in satisfactorily establishing the 
coefficient of friction which obtains at different velocities, owing to the 
fact that the time during which the pressure is continued to be applied 
enters so largely into the amount of friction produced by a given 
pressure. Thus in Fig. 16, with a speed of from 55 miles falling to 
about 53 miles per hour, a pressure of 35,000 lbs. at the commence- 
ment of the experiment produced a frictional resistance of about 2,000 
lbs., whilst after 10 seconds the amount of frictional resistance had 
diminished to 1,400 lbs., although the pressure maintained was the same. 
Similarly, in experiment No. 31 of 23d August, at a speed of 30 
miles an hour, a pressure of 12,000 lbs. produced at first a frictional 
resistance equivalent to 1,860 lbs.; but after 10 seconds this amount 
had fallen to 1,260 lbs., although the pressure had been raised to 
13,440 lbs. It thus appears that the amount of friction is greatly 
diminished as the surfaces continue in contact. But the full pressure 
cannot be applied absolutely instantaneously ; and however short the 
interval of time between the commencement of the experiment and the 
point at which the friction and pressure are measured, that interval is 
sufficient to affect the proportion which the friction bears to the pressure. 

The experiments with which the author has had to deal are more- 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^-^^ 



over so numerous, and their reduction has 
been a work of so much labour, that he 
is not yet prepared to say that the coeffi- 
cient of friction which he is about to give may not be Hable to some 
modification when he has had time for further collation of the results. 
With this reservation he appends the following table, which gives, it is 
believed, a fair approximation to the coefficient of friction at diiFerent 
velocities between cast-iron brake-blocks and steel tires as used in these 
experiments. 

Table I. — Static and Dynamic Friction. 





Velocity. 






Coefficient 


OF Friction. 












Obtained Approximately from 








Noted by 


Recent Experiments. 




Feet 


Miles 


Former _ 






Observers. . 


t Com- 












per 


per 


See Fleeming 


After 


After 


After 


After 




Second. 


Hour. 


Jenkin, Phil. " 


lence- 
lent of 


5 


10 


15 


20 








Trans, for " 

1877. ^ 


Sec- 


Sec- 


Sec- 


Sec- 








xperi- 
tnent. 


onds. 


onds. 


onds. 


onds. 


Static Friction. 
















Morin. — Iron on Iron 


Nil 


Nil 


•44 














' Steel on Cast- 






1 














iron at pres- 






t 












Rennie - 


sure of 1 80 
lbs. per square 
inch. 


Nil 


Nil 


.300 












do. < 


at 336 lbs. per 
square inch. 


Nil 


Nil 


.347 












Fleeming Jenkin. — J 
Steel on Steel 


.0002 


Inap- 


1 . 3 5 1 mean 












to 
.0086 


preci- 
able 


j .365 max. 












Dynamic Friction. 


















Cast-iron on Steel. 


















Just before coming to rest 


I to 3 


2^t02 




250 










When moving at . 


10 


6.8 








242 










do. 






20 


13.6 








213 


.193 








do. 






25 


17.0 








205 


•157 


. . 


.110 




do. 






30 


20.4 








182 


.152 


.133 


.116 


.099 


do. 






40 


27.3 








171 


.130 


.119 


.081 


.072 


do. 






45 


30.7 








163 


.107 


.099 






do. 






50 


34-1 








153 










do. 






55 


37.5 








152 


.096 


.083 


.069 




do. 






60 


40.9 








144 


.093 








do. 






70 


47-7 








132 


.080 


.070 






do. 






80 


54.5 








106 






.045 




do. 






88 


60.0 








072 


.063 


.058 







^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



This table indicates clearly the decrease 
in the coefficient of friction dependent 
upon increased velocity, and also the de- 
crease due to the increased time during which the surfaces continue in 
contact. Further collation of the results of the experiments already 
obtained will however be necessary before an endeavor is made to 
deduce the actual laws of these decreases. 

A certain number of experiments were made with wrought-iron 
blocks ; the results, so far as the coefficient of friction is concerned, are 
shown in the following table : — 

Table II. — Friction of Wrought-Iron Blocks on Steel Tires. 



Velocity. 


Coefficient of Friction. 
Wrought-Iron Blocks and Steel Tires. 


Feet per 
Second. 


Miles per 
Hour. 


At Commencement 
of Experiment 
to 3 Seconds. 


At from 5 to 7 
Seconds. 


At from 12 to 16 
Seconds. 


70 

45 
26 


48 
18 


_ .110 
.129 

.170 


.11 


.099 



These blocks were not satisfactory in their operation. The surface 
seemed to be much affected by the increased temperature resulting from 
the friction, and jerks were produced which threatened to damage the 
apparatus. 

The effect of sand on the rail, when fairly delivered under the wheel, 
is largely to increase the adhesion, both of the blocks and of the rails. 
Fig. 22, where the van was started from rest, exemplifies this. The 
average coefficient of friction whilst the wheels were revolving was 
.278, which is a much larger value than those given in Table i. Just 
before the skidding took place the frictional resistance was equal to 
about 4,400 lbs., or nearly .46 of the pressure applied, and about .40 
of the weight on the braked wheels ; which represents, therefore, the 
adhesion of the sanded rails. In the case of wet and greasy rails, sand 
appeared to make the adhesion about equal to that of a dry rail ; but on 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^""^'^^ 



a dry rail at high speeds sand did not 
appear to produce much effect, probably 
from being scattered by the wind caused 
by the motion of the van. 

It must always be borne in mind, in discussing these experiments, 
that, when high speeds are used, the disturbing causes are so great that 

it is only from the average of a large 
Experiment No. 16 number of experiments that useful re- 
Van starting from rest, sults can be obtained. 

Sand on rails. r> m • />/-•• i 7 

2. Loejficient oj friction between the 

Lbs.^ 

^^i^J-*''- C\ wheels and the rails, 

,^30 / \ / j When the rotation of the wheel has 

1' \ \ \ been arrested by the pressure of the 

' "~ I brake-blocks, and the wheel slides on 

■130 .' I 

,' 1 the rail, the retardation of the vehicle 

( I arises from the friction between the 

; I wheel and the rail. In this case the 

pressure arises from the weight of the 






I /|| vehicle on the rail. The friction 

r 

r 



Lbs. 
p. sq. in. 



.41"' — P :• >' \ /l^ v/ • 



::ii / ■■■■■■■' 



measured by the force which is exerted in holding the wheel in its 
fixed position, or by the force required to draw the skidded wheel along 
the rail, over and above that required when the wheel rotates freely. 
The experiments show that these forces are practically the same in amount. 
The experiments on the Brighton Railway were made chiefly upon 
steel rails ; but a certain number were made on a portion of the line 
where iron rails are in use. The following table gives approximately 
the coefficient of friction derived from these experiments : — 



^"^^•^^ Air Brake Tests 



Table III. — Dynamic Friction between Wheel and Rail. 



Approximate Velocity. 


Coefficient of Friction. 


Feet per Second, 


Miles per Hour. 


Steel Tire on Steel 
Rail. 


Steel Tire on Iron 
Rail. 


Just coming to 
rest . . 

lO 

20 
40 

50 
60 
70 
80 
88 


6.8 

13.6 

27 3 

34-1 
40.9 

47-7 
54.5 
60.0 


.242 
.088 
.072 
.070 
.065 
.057 
.040 
.038 
.027-^ 


.247 
.095 
.073 

.070 

.060 



■^ This is from a mean of three experiments only. 



It will be observed that there is some diiFerence between the friction 



Fig. 23 

Miles 
per liour. 
r60 - 



Experiment No. 17 

Slip Stop without Skidding. 
Gradieui fairing 1 in 1056. 



p. sq.iii. 



as noted with steel tires on 
iron rails, and with steel tires 
on steel rails ; the proportion 
which the friction bears to 
the pressure, or the coeffi- 
cient o^ friction, is greater 
in the case of iron rails than 
in the case of steel rails. 

The diminution in the 
coefficient of friction arising 
from the increasing time 
during which the surfaces 
are in contact is not so 
marked in the case of the 

wheel sliding on the rail as in that of the wheel revolving against the 

brake-blocks. 




GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^l£f 



The practical inference to be drawn 
from the results which have been obtained, 
as to the low coefficient of friction when 
the wheels slides on the rail, is exemplified in the experiments made on 
the Brighton Railway, where the van was detached from the engine when 
traveling at an ascertained speed, and allowed to come to rest. The 
diagrams shown in Figs. 23 and 24, afford a fair example of the disad- 
vantage of applying such an amount of pressure as will cause sufficient 
friction to stop the rotation of the w^heels, in cases where a rapid stop 
is required. In Fig. 24 the pressure applied amounted to 24,010 lbs.; 



Miles 
per hour. 


^ 




Fig. 3 4 Experiment I^o. 18 

Lbs. 
Slip Stop with Skidding. P- «|-^jj^ 






\ ' ~~ 


" ^. Gradient level. 






P ^. 








■^ *^. 96- 






y i 


•-^.. 




•50 


/\t 






. 


/ \/ 


^\ ""'" 60- 






/ V 


^^^-. 


^^"'Vn. 






^^-^ 50- 


p 


■40 
■30 


/ / 






f/ \ 


_ 


!.• s 


• 


--^ 20- 




■20 


I 




^>.^ 

F •••■ >-;:;•—••• ^^ 





'10 

=■0-1 .— 


-t^ — 1 r 


_^ 


^^-~- 


— 1 — 1 — I — 1 



this was rather more than twice the weight on the wheels, and was 
sufficient after a diminution had taken place in the speed of the van 
from 60 miles to somewhere about 52 miles per hour, to arrest the rota- 
tion of the wheels. On the other hand, in Fig. 10, the maximum pres- 
sure applied was about 1 7,500 lbs., which did not produce sufficient fric- 
tion to arrest the rotation of the wheels. In the experiment shown in 
Fig. 23 the van came to rest in 1 1 ^ seconds and in a distance of 189 
yards, on a descending gradient of i in 1056; in the experiment 
shown in Fig. 24 the van was more than 30 seconds in coming to 
rest on a level, and ran a distance of above 400 yards. 



^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



3. General effect of the application of 

the brakes in retarding the train, as 

shown by the strain on the draw-bar. 

The application of pressure to the brake-blocks, and the friction 
thereby produced, causes an immediate strain on the draw-bar propor- 
tional to this friction. This is very clearly shown in Figs. 16, 17, 18, 
25, 26, and 27, which are all selected from cases where the experiments 
took place on ascending gradients or on a level. It will be observed in 
these diagrams that the actual amount of friction increases with the 
pressure, up to a certain point ; and then, if the friction is not sufficient 
to stop the rotation of the wheel, the decrease in the coefficient of 
friction, arising from the time during which the surfaces are in contact, 
causes the actual friction to decrease ; and the strain on the draw-bar 
regularly follows the line of this decreasing friction. If, on the other 
hand, the pressure and consequent friction is sufficient to stop the rota- 
tion of the wheel, the strain on the draw-bar falls at once, on the 
rotation being checked, to a point corresponding with the diminished 
retardation resulting from the sliding of the wheel on the rail, as com- 
pared with the retardation caused by the friction of the brake-blocks on 
the wheel whilst the adhesion between wheel and rail acts freely to 
cause rotation. The draw-bar strain thus shown was in some cases not 
much more than twice as great as the ordinary tractive force previously 
shown to exist before the brake was appHed. 

Were there no disturbing causes when the brakes are applied to the 
wheels, and were a uniform speed maintained without skidding, the 
difference between the tractive force, or strain on the draw-bar, exerted 
after, and that exerted before, the application of the brakes would be 
equal to the friction between the brake-blocks and the wheels ; and thus 
the friction between the brake-blocks and the wheels is the measure of 
the retardation caused by the action of the brakes on the train. 

The next point to which attention may be directed in the diagrams 
is the following. When the rotation of the wheels has been arrested, 
the strain on the draw-bar, as aheady observed, becomes much less than 
that which prevailed v^hilst the wheels to which the brakes are appHed 
continue to rotate ; but when the pressure appHed to the brake-blocks 



Miles /I 
per hour i / 
r30 1/ s 




^^^^^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



is removed, so that the wheels whose 
rotation had been arrested begin to re- 
volve again, this release of the wheels, at 
the moment when they take up their rotation, occasions a sudden 
strain on the draw-bar ; because the adhesion between the wheels and 
the rails then comes into operation, and holds the wheels so as to com- 
pel them to rotate. 

Thus in Fig. 2 1 the friction between the brake-blocks and the wheels, 
which determined the point of skidding, was about 1,980 lbs., equivalent 
to .19 of the weight on the wheels ; this is the value of the adhesion 
between the wheels and the rails in the experiment in question. Now 
it will be seen that at the moment when the wheels were beginning to 
rotate, after the skidding, a strain was brought on the draw-bar of from 
1 ,900 to 2,000 lbs. (or from . 1 9 to . 20 of the weight upon the wheels) 
in excess of the average strain which the draw-bar showed after the 
wheels had acquired the rotation due to the forward movement of the 
train. Thus the extra strain on the draw-bar due to the wheels again 
taking up their rotation was equal to the adhesion, in the experiment in 
question ; and this appears to be the case generally. 

4. Proportion which the pressure applied to the brake-blocks should 
bear to the weight on the wheels at different velocities. 

The main practical advantage to be derived from the information 
given by these experiments, as to the coefficient of friction between 
brake-blocks and w^heels, is the assistance which it affords towards 
determining the degree of pressure that should be appHed to the brake- 
blocks in order to produce the required amount of retardation. 

It is the adhesion between the wheel and the rail which governs this 
question, and if the adhesion were always uniform the rule would be 
very simple ; but this is not the case. 

In the experiments now under discussion, the adhesion appears to 
have been on an average about .24 to .25 of the weight, but it was 
sometimes below .19, and sometimes higher than .25. Now it is 
clear that ( i ) the pressure which, if appHed, would stop the rotation 
of the wheels when the adhesion is low is much less than that which 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^^^ 



would stop the rotation when the adhe- 
sion is high ; and ( 2 ) the higher the 
pressure which is apphed, short of that 
which stops the rotation of the wheels, the greater is the friction and 
the consequent retardation of the train. 

The following table gives approximately the proportion which the 
pressure to be applied to the brake-blocks should bear to the weight 
upon the braked wheels, with coefficients of adhesion between wheel 
and rail varying from .30 to .15 of the weight on the wheels : — 
Table IV. — Ratio of Brake-block Pressure to Weight on Wheels. 









Approximate Ratio 




Speed. | 


of Total P 


ressure on Brake-blocks to Total Weight 








on Braked Wheels. 




Feet 


Miles 


Coefficient 


Coefficient 


Coefficient 


Coefficient 


per 


per 


of Adhesion, 


of Adhesion, 


of Adhesion, 


of Adhesion, 


Second. 


Hour. 


0.30. 


0.25. 


0.20. 


0.15. 


II 


1% 


1.20 


1.04 


0.83 


0.60 


22 


15 


1. 41 


1. 18 


0.94 


0.70 


29 


20 


1.64 


1.37 


1.09 


0.82 


44 


30 


1.83 


1-53 


1.22 


0.92 


59 


40 


2.07 


1.73 


1.38 


1.04 


73 


50 


2.48 


2.07 


1.65 


1.24 


88 


60 


4.14 


3-47 


2.77 


2.08 



It will be seen that, when the adhesion equals .30 of the weight, a 
pressure equal to 1.2 of the weight would skid the wheel at 7^ miles 
per hour, whilst a pressure equal to 4.14 times the weight would be 
required to do so at 60 miles per hour. On the other hand, if the 
adhesion is only .15, the pressure requisite to skid the wheel w^ould be 
only .60 of the weight at 7^ miles per hour, and 2.08 of the weight 
at 60 miles per hour. 

Thus the efficiency of a brake depends upon the pressure being pro- 
portioned to the speed and to the adhesion. Therefore every engine 
should be provided with a speed-indicator, in order that the driver may 
know with certainty the speed at which he is travelling. 

At present no means are in use by which the pressure can be regu- 
lated with a due regard to the adhesion, beyond those dependent upon 



^^^^^-^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



the judgment of the engine driver. There 
is, however, no reason why, in the prog- 
ress of mechanical science, both the 
above conditions should not be regulated by a self-acting arrangement. 
It may be added that the adhesion, and consequently the retarding 
effect of the brakes, would be greatly increased were means devised 
for placing sand under every wheel to which a brake is apphed during 
the progress of a stop. 

5. Effect of the time expended in bringing the pressure to bear 
on the wheels. 

The experiments made with the experimental van on the Brighton 
Railway showed the following results as to the times of stopping of the 
van, when released from the engine by a slip-coupling, at various 
speeds, and with both pairs of wheels braked : — 

Table V. — Stops of Van with Both Pairs of Wheels Braked. 





Speed. 




Distance 


Time 

of 
Stop. 


Average 

Retardation 

in Miles 

per Hour 


Ratio of 


Date and No. of 
Experiment. 


Miles 
per 


Gradients. 


or 
Stop. 


Retarding 

Force 
to Weight 




Hour. 




Yards. 


Seconds. 


per Second. 


on Wheels.* 


24 July, No. 25 


30 


Level 


63 


%y. 


6.8 


.16 


24 July, No. 28 


32 


do. 


75 


1% 


4.2 


•15 


25 July, No. 25 


40 


do. 


84 


9 


4-5 


.20 


25 July, No. 26 


40 


do. 


85 


9 


4-5 


.20 


22 Aug., No. 21 


S3 


do. 


H5 


12 


4.6 


.21 


23 Aug., No. 10 


5^ 


r Fall ^ 
\ I in 176 / 


151 


"% 


4-5 


•19 


24 July, No. 21 


60 


Level 


187 


11^ 


4-7 


.21 


22 Aug., No. 7 


60 


do. 


189 


12 


5-^ 


.21 


23 Aug., No. 18 


52 


do. 


215 


15 


3-5 


•14 



The rapidity of the stop depends much upon the rapidity with 
which the brakes are brought to bear on the wheels. This is illustrated 
by Figs. 28 and 29. In Fig. 28, the speed was 52 miles an hour ; 



■^ This ratio is deduced from the formula y : 



V2 

2gl 



, where f = ratio of retarding 



force to weight on wheel, V 1= initial velocity of train in feet per second, i 
run in coming to rest. The effect of gradients is neglected. 



feet 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^^^ 



the full pressure was brought on imme- 
diately, and the van was brought to rest 
in 1 1 ^ seconds and in i 5 i yards, on a 
descending gradient of i in 176. In Fig. 29 the speed was about 
5 2 miles an hour ; the pressure was applied gradually, beginning to 
be brought on after i second, and the stop took place in i 5 seconds 
and in 2 1 5 yards on a level. It is thus abundantly clear that the 
rapidity with which the pressure can be applied to the wheels through the 
medium of the brake-blocks materially influences the rapidity of the stop. 
This points to the advantage of being able to move the brake-blocks 
with great rapidity from their position of inaction to that of contact with 



Miles 
per hour 
-55 



Fig. 88 Experiment No. S« 

Slip Stop in 151 yards. 

suddeijiT— ^ i ••"> 




Fig. 39 Experiment No. 33 




the wheels; because it is essential to provide that the brake-blocks, when 
out of use, shall be removed to a distance from the wheels sufficient to 
prevent the possibility of their dragging against the wheels, and thus 
causing retardation to the progress of the train. The question of the 
rapidity with which brakes can be apphed in practice is thus one of 
much importance. Through the courtesy of the Directors of the 
North Eastern Railway, and their General Manager, Mr. Tennant, 
the author was enabled to make some experiments upon two trains, one 
fitted with the Westinghouse brake, the other with the Smith- Hardy 
Vacuum brake ; the object being to ascertain the rate at which the 
pressure upon the brake-blocks is applied in practice to the wheels of a 
train, in four different parts of the train, viz. : — 



^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



I St, Next to the engine ; 

2nd, At a distance of six carriages 

from the engine ; 
3rd, At a distance of twelve carriages from the engine ; 
4th, At a distance of twenty carriages from the engine. 
The trains upon which these experiments were made were as 
follows : — 

Table VI. — Weights of Trains. 



Total 


Weight. 


Weight on 
1 Braked Wheels. 


Tons. 


Cwt. 


Qrs. 


Tons. 


Cwt. 


Qrs. 


10 


18 











14 


9 





14 


9 





9 


10 





9 


10 





22 


n 





22 


13 





15 


16 


2 


15 


16 


2 


56 


II 


3 


56 


II 


2 


34 


12 


3 


34 


12 


2 


9 


12 





9 


12 






Westing house Train. — 

{Leading Wheels 
Driving do. 
Trailing do. 

Tender 

2 Vans 

Carriages — 6 Composite 

7 Third-Class 
Experimental Van . 



Total Westinghouse Train 174 



163 



Vacuum Train. — 

( Leading . 

Engine \ Driving . 

( Trailing . 

Tender 

2 Vans 

Carriages — 3 Composite 

7 Third-Class 
Experimental Van . 



12 


10 











14 








14 








12 


M 





12 


M 





26 


4 





26 


4 





15 


16 


2 


15 


16 


2 


28 


2 


I 


28 


2 


I 


60 


12 





60 


12 





9 


12 





9 


12 






Total Vacuum Train 



179 



167 



Therefore, in the case of the Westinghouse train, 93.7 per cent, of 
the weight, and in the case of the Vacuum, 94.4 per cent, of the weight, 
was on the braked wheels. The weight of the engine and tender 
resting on braked wheels was, in the case of the Westinghouse, 26.7 
per cent., and in the case of the Vacuum, 29.4 per cent., of the 
whole weight of the train. 

The recording apparatus in the van was set in motion by means of 
an electric connection with the brake lever attached to the engine. 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^^^ 



The author had intended this to come 
into operation at the first movement of 
the brake lever ; but by the arrangement 
made the lever could move through two- thirds of its stroke 
before setting the apparatus in motion ; so that, w^hen the handle 
of the lever w^as moved slow^ly, any action on the brakes vv^hich 
might take place before this point had been reached would not be 
recorded. 

The Westinghouse train was a train which had been working in 
regular traffic, and was run in practically the same condition as when 
running on the line, except that it was put in good order. The 
Vacuum carriages and engine were altered from what had been their 
condition on the North Eastern Railway, by the substitution of the 
Hardy cylinders for the Smith Vacuum sack, and by alterations in the 
ejector on the engine. On the ordinary passenger engines of the 
North Eastern Railway the bottom nozzles of the ejector are 2 in. 
diameter, and the top nozzles 2 ^ in. , and the steam pipe i ^ in. . In 
the experimental engine one of the bottom nozzles was 2^ in. 
diameter, and the other 2 in. diameter : the top nozzles 2^ in. diameter 
and 2^ in. respectively, and the steam pipe 2 in. inside diameter. 
The leverage was also much more powerful than that in use on the 
other passenger engines of the North Eastern Railway, so that a very 
high pressure could be applied to the engine wheels. These alterations, 
it was stated, were made in order to place the train in the same 
condition as trains recently fitted up on other lines. 

It was intended that the brakes should be so arranged that each 
brake-block, when in a state of inaction, should be removed a full 
quarter of an inch from the surface of the wheel, so as to ensure that 
there should be no dragging. This condition was fulfilled in the 
Westinghouse train ; but in the Vacuum train the blocks, except in 
two or three instances, were much closer, indeed often less than ^ 
inch, and in some cases less than ^V inch from the tire of the wheel. 
The Westinghouse train, as well as the experimental van, was fitted 
with continuous draw-bars. The Vacuum carriages had not continuous 
draw-bars. 



^^^^^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



The experiments were commenced by 
putting the van next the engine, and so 
running from York to Knaresboro' ; the 
van was then turned and placed at the tail of the train on the return 
journey. 

After the Vacuum train had made six stops with the van next the 
engine, during the journey to Knaresboro' , while making a stop on an 
ascending gradient of i in 120, a coupling-hook broke in the leading 
van, next behind the experimental van. A fresh connection was made, 
but it was found, on returning to York, that the vacuum cyhnder on 
the tender, for working the engine brakes, had become detached ; this 
was apparently caused by a want of sufficient play in the lever con- 
necting the Hardy cylinder with the engine brake. The experiments 
subsequent to the fracture rest under a doubt, therefore, as to repre- 
senting truly the performance of the Vacuum train. 

On the following day the van was placed in the middle of the train. 
In this case the first experiment was made with a speed of 50 miles 
per hour. There was a violent jerk, and the draw-bar of the leading 
van was torn out, and the train separated from the engine. As the 
Vacuum is not an automatic brake, the fracture caused the brakes to 
be taken off the train ; the rapid and judicious action taken by those in 
charge of the engine prevented, however, any serious collision between 
the engine and the train. 

These fractures of couplings appear to have been due to the more 
powerful and immediate appHcation of the brakes on the engine in 
these cases as compared with the rate at which the brake-blocks came 
on at the rear of the train ; the buffers were consequently driven 
home for a time, and then, at the moment when the reaction of the 
buffer- springs was commencing to have its effect, the brakes at the rear 
of the train also came into operation ; thus a violent, and in the last- 
mentioned case a successful, effort at separation occurred between the 
engine and train. 

After this accident the experiments were continued with eleven 
carriages instead of twelve, the van being fifth instead of sixth from 
the engine. The brake-lever was moved with caution ; the electrical 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests £^ 



68 



connection for starting the recording 
apparatus also acted irregularly, so that 
the diagrams of these further experiments 

present great discrepancies between themselves as to the rate at which 

the pressure came on. 

r'i 



Lbs. p. sq. in. 
rllO 




The author on this account obtained the permission of the North 
Eastern Railway to repeat these experiments, and the renewed trials 
took place on the i8th October. On this occasion the recording 
apparatus was set in motion by the first movement of the brake lever. 



^^^^^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



The experiments on the Westinghouse 
train were partly made by sHpping the 
experimental van and eleven carriages, 
and allowing the slipped portion to come to rest by the automatic 
action of the brakes. The experiments on the Vacuum train were a 
repetition of those of the second day ; in the course of the ninth experi- 
ment the draw-bar of the second vehicle from the engine gave 
way. 

Figs. 30 and 3 i show the results obtained from the two first days' 
experiments on the North Eastern Railway as to the rates at which the 
pressures and frictional resistances come into operation in each position 
of the van in the train ; and the accompanying table shows, as nearly 
as can be obtained from the diagrams, the time which was required 
after moving the brake-handle to set the brakes with various degrees of 
force in different parts of the train. The last experiment, where the 
van was the twenty-first vehicle from the engine, was made with a 
stationary train of twenty carriages, there being only twelve carriages 
available on the experimentaLtrain. 

Table VII. — Time Expended in Putting on Brakes. 





Vacuum Brake. 


Westinghouse 
Automatic Brake. 


Place of 
Experimental 

Van 
from Engine. 


Com- 
mencement 
of Move- 
ment of 
Blocks. 

Seconds 


Half 
On. 

Seconds. 


Three- 
quarters 
On. 

Seconds. 


Full 
On. 

Seconds. 


Com- 
mencement 
of Move- 
ment of 
Blocks. 

Seconds. 


Half 
On. 

Seconds. 


Three- 
quarters 
On. 

Seconds. 


Full 
On. 

Seconds. 


1st Vehicle 
yth do. . 

13th do. . 

2ist do. . 


2 

5^ 


3 

17 


7 

30 


II 
14 


% 

I 

3 


4>^ 


2 

3>^ 
5 


^y^ 
^y 



The short time which has elapsed since the above experiments were 
made has not allowed the author to analyse the results fiilly for the 
present meeting. They give, however, a fair approximate indication 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^^^ 



of the rate at which the pressure comes 
on, with these forms of brake, in differ- 
ent parts of a train. It was evident in 
the course of these experiments that the difference in the rapidity of 
application in the rear as compared with the front of the train gives rise 
to jerks and unpleasant motion in the process of stopping, if not to 
actual danger. They clearly show (as do also the experiments already 
mentioned on the Brighton Railway) that the perfection of a brake 
would consist in its appUcation being simultaneous on all the wheels of 
a train. 

The following table gives the particulars of the stops which took 
place in the experiments of all three days. On the first day the 
weather was very rainy and disagreeable ; on the 'second day the 
weather was fine ; on the third day the morning was foggy and damp, 
and the rails very greasy ; the afternoon was dry and fine. 



Table VIII. — Stops On North Eastern Railway. 

Vacuum Train. — First Day. 

( Van next Engine. ) 













Distance 






Speed. 


Distance 


Time 


Gradient. 


Reduced 




No. 


Miles 


of 
Stop. 


of 
Stop. 


R — Rise. 


to 

50 Miles 


Remarks. 




per 
hour. 


Yards. 


Seconds. 


F=Fall. 


per hour. 
Yards. 




I 


40 


211 




R I in 130 . 


329 


Heavy rain. 


2 


35 


154 


14 


R I in 130 . 


314 


do. 


3 


40 


220 


17 


F I in 1200 . 


343 


do. 


4 


43 


228 


17 


Level . . . 


308 


do. 


5 


49 


294 


20X 


do. ... 


306 


do. 


6 


35 


162 


15 


do. ... 


330 


do. 


7 


35 


154 


hX 


R I in 120 . 


314 


Broke coupling. 


8 


49/^ 


316 


21 


Level . . . 


322 




9 


53 


325 


i8>^ 


do. ... 


289 


Heavy rain. 


lO 


%o% 


334 


21 


do. . . . 


327 


do. 


II 


35 


162 


14^ 


R I in 1200 . 


330 


do. 


12 


47^ 


281 


20 


F I in 130 . 


311 


do. 


13 


32 


136 


13.3/ 


F I in 130 . 


332 


do. 


14 


28 


114 


I2X 


F I in 1 30 . 


376 


do. 


15 


31 


136 


14 


F I in 130 . 


353 


do. 



''"^^ ^' Air Brake Tests 





Vacuum 


Train. — 


Second Day. (Van in middle of train.) 




Speed. 


Distance 
of 

Stop. 


Time 

of 
Stop. 


Gradient. 


Distance 
Reduced to 




No. 


Miles 
per 


R=Rise. 


50 Miles 
per Hour. 


Remarks. 




Hour. 


Yards. 


Seconds. 


F=Fall. 


Yards. 
















j Broke draw-bar of 


22 


49 


440 


WA 


Level . . . 


458 


\ leading van. 


2^ 


39 


^158 


13/2 


F I in 1200 . 


259 


Fine. Good rail. 


26 


43 


^184 


i4>^ 


R I in 130 . 


248 


do. 


27 


37 


•5^-132 


121^ 


Level . . . 


241 


do. 


28 


41 


^162 


133^ 


R I in 120 


240 


do. 


29 


50 


^246 


16^ 


Level . . . 


246 


do. 


30 


5.5 >^ 


^299 


183^ 


do. . . . 


242 


do. 


31 


36 


^140 


13 


F I in 130 


270 


do. 


32 


35 


*I23 


12 


F I in 130 


251 


do. 



^ These distances are not reliable, owing to slow action of recording apparatus. 



Vacuum Train. — Third Day (repeated 


experiments ) . ( Van 


n middle of train. ) 




Speed. 


Distance 
of 


Time 
of 




Distance 
Reduced to 




No. 


Miles 
per 


Stop. 


Stop. 


Gradient. 


50 Miles 
per Hour. 


Remarks. 




Hour. 


Yards. 


Seconds. 




Yards. 




7 


53 


308 


19 


Level . . . 


274 


1 




8 


41K 


193 


14K 


do. . 








280 






9 


49^ 
35 


255 
145 


12^ 


do. . 








258. 






10 


do. . 




296 


Fine. 


II 


57>^ 


356 


20 


do. . 






269 


Very good rail- 


12 


57 


334 


19/2 


do. . 








257 I 




13 


57 


352 


21 


do. . 








271 






14 


53 


312 


19% 


do. . 








278 


J 




15 


35 


193 


22 


F I in 


130 




394 


Draw-bar broke. 









^Vesting house Train. — Second Day. 






Speed. 


Distance 


Time 




Distance 






of 


of 




Reduced to 




No. 


Miles 


Stop. 


Stop. 


Gradient. 


50 Miles 
per Hour. 


Remarks. 




Hour. 


Yards. 


Seconds. 




Yards. 




18 


43 


180 


14 


Level . . . 


243 


Damp, without rain. 


19 


30 


114 


121^ 


do. . . . 


316 


do. 


20 


46 


211 


^S/z 


do. . . . 


249 


do. 


21 


37 


140 


12/3 


do. . . . 


255 


do. 


22 


35 


123 


11^2 


R I in 120 . 


251 


do. 


24 


56 


316 


I9X 


F I in 130 


251 


do. 


25 


35 


132 


12 


Level . . . 


289 


do. 


26 


40 


162 


14 


R I in 1200 . 


253 


do. 


27 


50 


246 


ijVz 


Level . . . 


246 


do. 


28 


41K 


171 


14 


do. or F I in 130 


248 


do. 


29 


35 


123 


12 


F I in 130 


251 


do. 


30 


28 


88 


10 


F I in 130 


280 


do. 



Air Brake Tests ^""^'^^ 



JVestinghouse Train. — Second Day. 





Speed. 

Miles 

per 


Distance 
of 


Time 
of 


Gradient. 


Distance 
Reduced to 




No. 


Stop. 


Stop. 


R=Rise. 


50 Miles 
per Hour. 


Remarks. 




Hour. 


Yards. 


Seconds. 


F=Fall. 


Yards. 




I 


51 


281 


18^ 


Level . . . 


270 


Fine. Greasy rail. 


2 


41 


184 


15 


F I in 1200 . 


273 


do. 


3 


48 


215 


15^ 


Level . . . 


233 


do. 


4 


30 


88 


9% 


do. . . . 


244 


do. 


S 


36 


149 


^lYz 


do. . . . 


287 


do. 


6 


50 


264 


I8X 


do 


264 


do. 


7 


37^ 


140 


I2K 


do. . . . 


248 


do. 


8 


56 


334 


20^ 


do. . . . 


266 


do. 


9 


56 


299 


19 


do. . . . 


238 


do. 


lO 


3« 


149 


1354 


do. . . . 


257 


do. 


II 


36 


132 


12 


do. . . . 


254 


do. 


12 


31^ 


no 


"K 


do. . . . 


277 


do. 


13 


50 


255 


^ri 


R I in 1200 . 


255 


Good rail. 


14 


40 


159 


14 


Lev. or F. 1 30 


248 


do. 


M 


35 


132 


i^M 


F I in 130 


269 


do. 


i6 


32>^ 


96 


loX 


F I in 130 


227 


do. 


i8 


59^ 


404 


23 


Level . . . 


285 


do. 


19 


59 


378 


22^ 


do. . . . 


271 


do. 
r Signal from driver. 
\ Good rail. 


20 


45 


202 


15 


do. . . . 


249 


21 


55 


290 


19 


do. . . . 


239 


Good rail. 


22 


50 


246 


I7X 


F I in 130 


246 


do. No diagram. 



Westinghouse Train. — Third Day. (Van next Engine.) 



No. 


Speed. 
Miles 

per 
Hour. 


Distance 

of 

Stop. 

Yards. 


Time 

of 
Stop. 

Seconds. 


Gradient. 


Distance 

Reduced to 

50 Miles 

per Hour. 

Yards. 


Remarks. 


I 


43 


228 


16 


R I in 130 . 


308 




Damp and very greasy 
rail. 


2 


58 


294 


18 


Level . . . 


218 




- Eleven carriages and 


3 


57 


259 


17 


do. . . . 


199 


- 


experimental van 
let slip from engine. 


4 
5 


59 
58 


506 

378 


^7X 
22 


F I in 130 
Level . . . 


363 

280 




Very greasy rail. 
- Stops made with 
engine and train. 


6 


55 


316 


20 


do. . . . 


261 







^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



Conclusions, — In conclusion, the 
author would recapitulate what appear 
from these experiments to be the essential 
conditions of a good brake, in addition to other matters not coming 
immediately within the scope of this inquiry. 

1st. The skidding of the wheel, so that it slides on the rail, is 
altogether a mistake, so far as rapid stopping is concerned. 

2nd. The pressure with which the brake-blocks are applied to the 
wheels should be as high as possible, short of the point which would 
cause the wheels to be skidded and to slide on the rails. 

3rd. The rotation of the wheel is arrested as soon as the friction 
between the brake-block and the wheel exceeds the adhesion between 
the wheel and the rail ; and therefore the amount of pressure which 
should be applied to the wheel is a function of the weight which the 
wheel brings upon the rail. The value of this function varies with 
the adhesion ; hence, with a high adhesion a greater pressure can 
be applied, and a greater measure of retardation obtained, than with a 
low one. — 

4th. In practice and as a question of safety it is of the greatest 
importance that, in the case of a train travelling at a high speed, that 
speed should be reduced as rapidly as possible on the first application of 
the brakes. For instance, a brake which reduces the speed from 60 
miles an hour to 20 miles an hour, in say 6 seconds, has a great 
advantage as regards safety over a brake which would only reduce the 
speed from 60 to 40 miles an hour in the same time. 

5th. The friction produced by the pressure of the brake-block on 
the wheel is less as the speed of the train is greater ; to produce the 
maximum retardation so far as speed is concerned, the pressure should 
thus be greatest on first application ; and should be diminished as the 
speed decreases, in order to prevent the wheels from being skidded (or 
sliding on the rails) in making a stop. It should be added that the 
coefficient of friction decreases as the time increases during which the 
brakes are kept on ; but this decrease is slower than the increase of the 
same coefficient due to the decrease of speed ; it has therefore Httle 
influence in the case of quick stops. 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^^^ 



6th. The maximum pressure should be 
applied to the wheels as rapidly as possible, 
and uniformly in all parts of the train. 

7th. To prevent retardation from the dragging of the brake-Hocks 
against the wheels when the brakes are not in use, care should be taken 
that the brake-blocks are kept well clear of the wheels (say half an 
inch) when in a state of inaction. 

There are various mechanical questions connected with brakes, such 
as the desirability of automatic action, and other considerations, which 
do not enter into the scope of the present inquiry ; the special object 
of which was to ascertain by direct experiment the forces brought into 
action in applying the brake-blocks to the wheels. 

Railway companies, in considering what form of brake is best suited 
for traffic, must, whilst they give full weight to the mechanical con- 
ditions discussed in this paper, also consider the question of the 
convenience of any particular form of brake, and ascertain its durability 
and facility of maintenance and repair. It is further clear from 
the present series of experiments that the universal application of 
continuous brakes will raise many questions as to the strength of the 
rolling stock now in use, much of which was constructed originally 
to meet other conditions of traffic. 

In concluding this paper, the author would again apologise to the 
Institution for its incomplete character : the fact being that the 
enormous mass of information which has been collected has entailed 
so much detailed study that he has only been able to bring before the 
meeting on this occasion the present very incomplete sketch. He 
hopes on the next occasion to be able to complete his contribution 
upon this important subject. 

He has to repeat his thanks to Mr. Westinghouse for the beautiful 
apparatus contrived by him ; and for the very valuable assistance he 
has rendered in carrying out these experiments. 

He would further beg to tender his best thanks to the Directors 
of the Brighton Railway Company, and to their able and energetic 
Manager, Mr. Knight, and their able Locomotive Superintendent, 
Mr. Stroudley, for their cooperation and assistance in the enquiry. 



I 



I 



^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



without which it could neither have been 
commenced nor carried out. 

He has also to thank the Directors of 
the North Eastern Railway Company, and their able Manager, Mr. 
Tennant, for their courteous assistance in elucidating this difficult subject. 



Captain Galton explained at the close of his paper that the results 
of the second day' s experiments with the vacuum train, given in Table 
VIII., were practically superseded by those of the third day's experi- 
ments, given just after. The distances given in the former case were 
subject to some question, owing to discrepancies which he had found 
in the diagrams ; and therefore the second table of results should stand 
instead of the first. 



)0( 



ON THE EFFECT OF BRAKES UPON RAILWAY TRAINS. 

( Third Paper.) 



By Captain DOUGLAS GALTON, C.B., Hon. D.C.L., F.R.S. 



In the previous papers upon this subject which the author brought to 
the notice of the members of the Institution in June and October, 1878, 
it has been explained that it was anticipated, when the experiments 
were begun on the Brighton Railway with the van fitted with the self- 
recording apparatus, that the results would enable a rule to be laid 
down determining the amount of brake-block pressure, in proportion to 
the weight of the vehicles, which should be applied to the wheels of 
railway trains. 



Miles 
per Uour 



-m 


Fie. 32 


"^0 


\p •■■ ij' 


- K !i *• ? 

-jo: \ ;! 


1/ \ i 


-3«i Y i 

-crh— 1 — \ — r-V-r— 1 — \ — \ — \ — 1 — \ — 1 — r^r^""i 



V 


Fig. 33 


A Force 










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* 10- 



Effect of Skidding. 

It was immediately discovered, however, that the retarding eiFect of 
a wheel sliding upon a rail was much less than when braked with such 
a force as would just allow it to continue to revolve. 

The above copies of two sets of diagrams. Figs. 32 and 33, taken 
during the experiments, show, more clearly than can be explained, the 
difference in the retarding force, before the wheels begin to slide upon 



^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



the rails, and after. These two experi- 
ments were made with a single van 
slipped from the engine, the brakes going 
on automatically at the moment when separation from the engine took 
place. These and all the other diagrams illustrating this paper are simi- 
lar to those given in the second Paper. The line S S shows the speed 
of the braked wheels at each instant, the scale for which is given in 
miles per hour. The line P P represents the pressure against four 
blocks acting upon one pair of wheels : the vertical height of P on the 
scale headed ''force," when multiplied by 240, gives the total pressure 
in pounds on the four blocks collectively. The line F F shows the re- 
tarding eiFect of the four blocks upon the one pair of wheels before the 
wheels began to slide upon the rails ; and yy shows the effect while the 
wheels were sliding upon the rails. The vertical height of F oryon 
the scale of force, multipHed by 60, gives the total retardation in pounds 
upon that pair of wheels. 

The calculations show that the friction between the wheel and the 
rail, when th^ wheel is sliding on the rail, is less than one -third of the 
friction produced between the brake-blocks and the wheel, when the 
brake-blocks are so applied as to allow the wheel to continue revolving. 

Coefficient of Friction as affected by Speed. 

The next important discovery was, that the coefficient of friction 
between the brake-blocks and the wheels varied inversely according to 
the speed of the train, a higher proportion of brake-block pressure to 
weight being required at high speeds, and a lower pressure for a lower 
speed. This was illustrated by the diagrams shown in Figs. 16, 17, 
19, 20 of the second Paper. 

Table I. given in the second Paper for the values of this coefficient 
at different speeds has since then been somewhat altered by obtaining a 
mean from a considerably larger number of experiments. The accom- 
panying Table IX. shows the altered result. 

Coefficient of Friction as affected by Time. 
If the friction of the brake-blocks were always the same at the same 
speed, some simple rule might still be deduced which would give the 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^""^'^^ 



pressure required at each speed for obtain- 
ing a certain amount of retardation ; but 
when the speed of the van was kept nearly 
uniform by the effort of the engine, the friction of the blocks decreased ; 
and this occurred notwithstanding a continued increase of the brake- 
block pressure : showing that, through some cause not yet fully deter- 
mined, the holding power of brake-blocks at all speeds is considerably 
less after some seconds of application then when first applied. This 
peculiarity is illustrated by Figs. i6, 17, 18 of the second Paper. 
Hence the question of the proper amount of brake force needed at each 
instant, during the time required to stop a train, is still further compH- 
cated by this decrease which occurs in the coefficient of friction after the 
brakes have been applied, and which results from the time during which 



Table IX. — Coefficient of Friction at Varying Speeds. 
Cast-Iron Brake-Blocks on Steel Tires. 



Number of 


Velocity. 


Coefficient 


OF Friction. 


Experiments 












from which the 
Mean is Taken. 


Miles per 
Hour. 


Feet per 


Extremes Observed. 


Mean. 




Second. .. 
Ma 


ximum. Mi 


nimum. 


12 


60 


88 


123 


058 


.074 


67 


55 


81 


136 


060 


.III 


55 


50 


73 


153 


050 


.116 


77 


45 


66 


179 


083 


.127 


70 


40 


59 


194 


088 


.140 


80 


35 


51 


197 


087 


.142 


94 


30 


44 


196 


098 


.164 


70 


25 


36>^ 


205 


108 


.166 


69 


20 


29 


240 


.133 


.192 


78 


15 


22 


280 


131 


.223 


54 


10 


i4>^ 


281 


161 


.242 


28 


1% 


II 


325 


123 


.244 


20 


Under 5 


Under 7 


340 


156 


.273 




Just moving 


Just moving 






.330 


Fleeming Jenkin (steel on steel) 


.0002 to .0086 


337 


365 


•351 


Rennie. Static Friction under 








Pressure of 1 80 lbs. per squai 
Pressure of 3 'J 6 Ihs. oer sonar 


"e inch .... 






. 700 


e inch .... 






.347 




J r -1 









^"^^^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



they are kept applied, irrespective of any 
change in speed. This decrease in the 
coefficient of friction was shown in Table 
I. of the second Paper, from which the following figures are taken : — 

Table X. — Coefficient of Friction as Affected by Time. 



Speed. 


Coefficient of Friction. 


Miles 


Commencement 

of 

Experiment.* 


After 


After 


After 


After 


per Hour. 


5 Seconds. 


10 Seconds. 


15 Seconds. 


20 Seconds. 


20 


.182 


.152 


•133 


.116 


.099 


27 


.171 


.130 


.119 


.081 


.072 


37 


.152 


.096 


.083 


.069 




47 


.132 


.080 


.070 






60 


.072 


.063 


.058 







■^ The figures in this column are somewhat different from those that have just been 
given in the altered Table IX., because they resulted from the average of fewer 
experiments 5 but the effect of time in reducing the coefficient of friction may be 
accepted as correct. 

The decrease in the coefficient of friction arising from time some- 
times overcomes the increase in the coefficient of friction arising from a 
decrease in speed, especially when, either from the stop being on a 
descending gradient or from a small proportion of the train only being 







F 


ig. 34 










p 


v., 
i 










100- 


mies 








/ 




















90- 


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80- 


-50 




_^ ^ 










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70- 




II 




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Sj 










60- 


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ll 


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-10 
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Si 


T 1 


si 

1 1 1 1 r 












a; 








v^ 


10- 
0- 



30 Sec 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ''"^^^^ 



fitted with brake power, the train takes 
a considerable time in coming to rest. 
Therefore a higher brake pressure is re- 
quired in such cases than when the stop is made in a short time. 

The accompanying diagram. Fig. 34, shows a uniform coefficient of 
friction with a practically uniform speed, as obtained by means of an 
increasing brake-block pressure. The line P P shows the pressure, F F 
the friction (the coefficient of which is given for several ordinates), and 
S S the speed, which latter decreased slightly during the experiment, and 
would have caused an increase in the coefficient of friction had it not 
been counteracted by the element of time. 

Coefficient of Friction affected by Material and Weather, 

On experimenting further, it was found that the coefficient of friction 
was also influenced by the kind of metal in the blocks, and by the 
state of the weather. 

Experiments on a Train cannot be free from Disturbing Elements, 

The experiments were made upon trains travelling under conditions 
which of necessity were continually varying, and therefore presented 
many elements of disturbance beyond the reach of calculation. 

The time during which the pressure was applied has been shown to 
enter largely into the question, and this element of disturbance is in 
operation during the interval of time (however short) which neces- 
sarily occurs between the moment when the block first touches the 
wheel and the moment when the full pressure is obtained. 

Under these circumstances the author has limited himself to stating 
the facts obtained in the experiments, and has refrained from endeavour- 
ing to lay down the law of decrease in the coefficient of friction 
according to velocity ; as he beheves that any law which could be laid 
down would only tend to mislead, owing to the continually varying 
conditions which occur in practice. 

The Institution of Mechanical Engineers has decided to carry on 
through the medium of their Research Committee further experiments 
on this very interesdng subject ; and if these new experiments can be 



GALTON- 

WESTINGHOUSE 

TESTS 



^^^^^^ Air Brake Tests 

arranged so as to be free from the dis- 
turbing elements incidental to those which 
he has had the opportunity of making, 
the author trusts that the question will soon receive friller elucidation. 

Adhesion as affecting the Maximum Retardation, 

Notwithstanding the variations in the coefficient of friction between 
the blocks and wheels, it was found that under similar circumstances 
the adhesion of the wheels to the rails was practically constant, but 
that it varied according to the material — that is, whether the train was 
travelling upon iron or steel rails ; and according to the state of the 
rails, whether dry, wet, or sanded. 

On dry rails it was found that the coefficient of adhesion of the 
wheels was generally over .20. In some cases it rose to .25 or even 
higher. On wet or greasy rails, without sand, it fell as low as .15 in 
one experiment, but averaged about .18. With the use of sand on wet 
rails it was above .20 at all times ; and when the sand was applied at 
the moment of starting, so that the wind of the rotating wheels did not 
tend to blow it away, it rose up to .35, and even above .40. 

The retarding force which causes a train to be stopped by the applica- 
tion of brakes is limited to the adhesion or resistance obtained between 
the wheel and the rail ; therefore the greatest effect in stopping a train 
is produced when the friction between the brake-blocks and the wheel 
amounts to a quantity just short of the adhesion ; because as soon as 
the brake-block friction exceeds the adhesion, the wheel becomes fixed 
and begins to slide. 

If a certain amount of brake force or brake-block pressure would 
produce an equal amount of friction at all speeds, then the greatest 
possible amount of retardation during the time required to make a stop 
could easily be obtained ; but, as has already been proved, the brake 
pressure at high speeds must be much greater than at low speeds, in 
order to produce the same amount of retardation. 

The friction increases as the speed decreases, according to some law, 
which is complicated, as shown above, by the time during which the 
brakes have been applied. If therefore the pressure necessary to cause 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^''^'^' 



sufficient friction to balance the adhesion 
at a high speed be continued till the train 
comes to rest, the friction will increase 

and gradually overcome the adhesion, and the wheels will become fixed. 

This is illustrated by Fig. 1 9, page 5 1 . 

Therefore, in order to secure the best results in stopping, it is 

obviously necessary that the brake-block pressure should be so regulated 

as to give a friction about equal to the adhesion of the wheels at every 

stage during the process of stopping. 

Regulator for. Brake-block Pressure, 

In some of the former experiments on the Brighton Railway a pres- 
sure-reducing valve was introduced by Mr. Westinghouse, with the 
view of reducing the brake-block pressure as the speed was reduced ; 
and excellent results were obtained. And it will be recollected that 
the author, in his last paper, pointed out the possibility of devis- 
ing some self-acting apparatus whereby the friction between the blocks 
and wheels should actually regulate the pressure put upon the blocks, 
and keep it at the precise amount required. 

Mr. Westinghouse has since devised a new valve, so arranged in 
connection with one of the brake-blocks that the friction between the 
block and wheel regulates the pressure upon the blocks. The author 
had the opportunity of making some experiments on the Brighton Rail- 
way on 20th January, 1879, ^^^ ^^ purpose of testing this new valve. 
These experiments are very interesting, as tending to elucidate this part 
of the subject. The valve, as then used for the first time, was found 
to regulate the pressure of the brake-blocks against the wheels, and to 
reduce the pressure as required, except at the last moment, when the 
escape port was incapable in some cases of discharging the air fast 
enough to prevent skidding for a very short distance. It was also 
found that there was a needless waste of air from the reservoir. From 
the experience gained, a slight alteration has been made, which obviates 
the above difficulties. 

The genera] arrangement of the regulating valve as applied to 
railway carriages is shown in Fig. 35 ; Figs. 36 and '^'] are 



oo 




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h 


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■S 


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^4 
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< 



J 




GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^""^'^^ 



enlarged sections of the valve itself, the 
first in the normal condition when it is 
closed, and the second w^hen it is opened 
to reduce the pressure. In order to understand the action of the valve, 
suppose that four blocks act against a pair of w^heels, the load at A (Fig. 
35) on the two wheels being 10,000 lbs. The lever B is of such a 
proportion that the block C has 3 lbs. pressure upon it for every 2 lbs. on 
the block D. If the coefficient of adhesion at A is . 20, the. total adhesion 
is equal to 2,000 lbs. for the two wheels, or 1,000 lbs. for each wheel. 
If the rotating momentum of the wheels be taken as equivalent to 
an increase of -X- of the weight at A, then the four brake-blocks will 
have to oiFer a resistance of 2,200 lbs. to the two wheels, or i, 1 10 lbs. 
to one wheel, in order to obtain a result equal to .20 of the load at A. 
If the friction of the blocks C and D on one wheel together equals 
1,100 lbs., then, owing to the proportion of pressure upon them, the 
resistance offered by C will be 660 lbs., and by D 440 lbs. The 
block C is suspended from one end of a lever E, the opposite end of 
which, acting through a link L, tends to move one or other arm of the 
double bell-crank lever F. The form of this lever F provides for the 
rotation of the wheel in either direction. The lever E has a proportion 
of 6^ to I, and consequently requires 97.7 lbs. at its long end, to 
equal 660 lbs., the assumed friction of the block C. 

The motion of the lever F, Figs. 36 and 37, is resisted by the bolt 
G and spring H. When, however, the force on the link L is suf- 
ficient to move the bolt G and compress the spring H, a plug valve J 
in a case K is moved by the bolt. This valve communicates with the 
triple valve and air-reservoir by, the pipe P, and with the brake-cylinder 
by the pipe M ; while N N are openings to the external air. When 
the regulating valve J is closed (Fig. 36) these openings are shut, and 
the passage from the reservoir to the brake-cylinder is open ; but when 
the valve J is pushed inwards by the bolt G, it first closes the passage 
of air from the reservoir to the brake-cylinder, and, then, if moved slightly 
further, it opens the passage from the brake-cylinder to the atmosphere, 
thereby reducing the pressure of the air in the brake-cylinder, accord- 
ing to the area of the passage and the time during which it is kept open. 



GALTON-WESTINGHOUSE TESTS 

Enlarged Sections of Friction-Regulating Valve. 
Fig. 36 

Air Outlet closed. 




GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^"^'^^ 



The spring H alone offers 75^ lbs. re- 
sistance to compression, which is equiva- 
lent to a coefficient of adhesion of . 1 5 
between the wheel and the rail. The regulating valve J has slightly 
over .3 sq. in. area, and if acted upon by an air pressure from the 
reservoir of 75 lbs. per sq. in. it gives an additional resistance of 22^ 
lbs., making a total resistance of 98 lbs., equivalent to a coefficient of 
adhesion of .20. If a pressure of only 37^ lbs. per sq. in. be admit- 
ted to act upon the valve J, the total resistance against the lever E will 
be only 86.6 lbs., equivalent to a coefficient of adhesion of .175. 
Thus it will be seen that by simply regulating the air pressure in the 
reservoirs under the carriages, a considerable variation in the resistance 
can be made according to the state of the rails. One of these regulat- 
ing valves is put on each carriage, and the spring H and valve J are 
alike in all. 

The lever E must be proportioned according to the load at A ; and 
with the arrangement of brake levers and blocks shown in Fig. 35, the 
long end will be to the short end as i ^ to i for a load of i ton on 
each pair of wheels, or as 7^ to i for a load of 5 tons. If the brake 
levers and blocks were not arranged as shown, the proportion of the 
lever would have to be altered, so that the actual amount of resistance 
on the short end should give 98 lbs. pressure on the long end. It is 
essential in the use of this regulating valve, if one valve is to operate for 
the whole carriage, that the brake gear should be so arranged that any 
one block can act as a fulcrum for all the others. By this arrangement 
it becomes a simple matter so to regulate the brake pressure as to pro- 
duce a definite maximum amount of brake resistance ; the amount thus 
fixed should equal the highest average amount required. 

The regulating valve can thus be arranged so as to prevent the skid- 
ding of the wheels : and by the fact that it closes the passage for the 
air from the reservoir to the brake-cylinder before it allows any escape 
of air from that cylinder to the atmosphere, it possesses the property of 
permitting a high working pressure to be constantly maintained in the 
reservoir, without the danger of ever getting too high a pressure in the 
brake-cylinder. At the same time, if, after the valve has been opened 



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GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^""^'^^ 



to the atmosphere, an increased pressure 
on the brake-blocks is again required in 
order to compensate for the diminution of 
friction owing to lapse of time or to other causes, the decreasing friction 
will allow the valve to close the escape orifice from the brake-cylinder 
and reopen the connection to the air reservoir ; it will thus replenish the 
cylinder with the original high pressure of air, which may be again 
reduced and again restored by the valve, as may be required. 

Experiments made with the Friction Regulating Valve, 

The preceding Table XL shows several of the experiments made 
on 20th January, 1879, by slipping the experimental van from the 



Fig. 38 




\ FIs. 39 




Force 
90- 

80- 

70- 

60- 


¥ \ 




60- 


^^-\^ 


F 
\ 


40- 
30- 






20- 


1 \s 




10- 


? 


"^ 




«'■''' i ''■' I'o '' ' 




15 Sec. 



engine and bringing it to rest by means of the brake applied to all 
four wheels. 

The diagrams. Figs. 38 to 42, which have been selected from the 
experiments shown in Table XI., sufficiently illustrate the action of the 
regulating valve. These diagrams show also very clearly the variation 
in the coefficient of friction according to speed. 

In the experiment. Fig. 38, the van was stopped from a speed of 60 
miles per hour in i 2 seconds on a rising gradient of i in 264. The maxi- 
mum brake-block pressure on all the four wheels was 160 per cent, of 
the weight on the wheels at the beginning, and was reduced to 1 1 4 
per cent, at the end. The friction increased toward the end of the 



^"^^^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



experiment so much as to cause the 
wheels to skid just at the end. The 
adhesion shown was about .25. In this 
case the pressure was not reduced sufficiently to keep the friction uniform. 

Had this stop been made on a steep descent, or had the brake-blocks 
been acting on only one pair of wheels, the time required to effect the 
stop would have been greater ; and consequently the brake-block pres- 
sure, instead of being reduced, must have been increased, so as to 
overcome the decrease in the holding power of the blocks which results 
from the length of time of application irrespective of the speed. 

In the experiment. Fig. 39, the van was stopped from a speed of 57 
miles an hour on a rising gradient of i in 264 in 15 seconds. In this 



Porce 
80-1 




case the brake-block pressure was 114 per cent, of weight on wheels at 
the beginning of the experiment, and was reduced to .54 per cent, 
towards the end. The total friction of the brake-blocks on the four 
wheels may be estimated, from the actual friction obtained for one pair 
of wheels, at 3,244 lbs. at the beginning of the experiment, and 
3,144 lbs. in the middle, thus remaining very nearly constant; and it 
slightly increased to 3,400 lbs. towards the end. There was no 
skidding ; but the greater length of time occupied in the stop shows 
that the pressure was not sufficiently high at the beginning. 

Fig. 40 shows a stop from a speed of 5 5 miles an hour in 12 
seconds, on a falling gradient of i in 264. The brake-block pressure 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests £^fff 



at the beginning of the experiment was 
143 per cent, of weight on wheels, and 
was reduced to 1 06 per cent, at the end. 
The resulting friction as estimated for the brake-blocks on the four 
wheels is 4,473 lbs. at the beginning, and 4,574 lbs. in the middle of 
the experiment, after which, as the pressure was not reduced with 
sufficient rapidity, it rose rapidly, and caused a skid at the end. The 
adhesion shown was about .25. In this case the stop made was much 
better than that shown in Fig. 39, because of the greater initial pressure 
and greater consequent friction. 

Fig. 41 also illustrates this point by showing a stop from a speed of 
5 5 miles an hour on a level in 1 8 seconds. The brake-block pressure 
was 87 per cent, of weight on wheels at the beginning, and 40 per 
cent, at the end ; and the consequent estimated friction was only 
2,825 lbs. at the beginning, and 2,530 lbs. at the end; consequently 
a longer time was required for making the stop. 

Fig. 42 further illustrates 
the necessity of a high 
pressure on the first appli- 
cation of the brakes, if a 
rapid stop is to be effected. 
The heavy lines show the 
speed S, pressure P, and 
friction F, in a stop made 
from 60 miles an hour on 
a rising gradient of i in 
311. The brake-block 
pressure was 162 per 
cent., or nearly two-thirds 
more than the weight on 
the wheels at the beginning of the experiment, but it was not reduced 
with sufficient rapidity ; hence one pair of wheels skidded at the end of 
9 seconds, at which time the speed was reduced to about i 7 n.iles per 
hour; and, notwithstanding this skidding, the van came to rest in 167 
yards and in i 2 i^ seconds. The light lines give the speed /, pressure 




^""seQi jiir Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



py and friction y^ of the stop shown in Fig. 

4 1 ; and it will be seen that from an initial 

velocity of 55 miles an hour, and with 

a maximum brake-block pressure of about 87 per cent, of weight on 

wheels, the speed at the end of nine seconds had only been reduced 

to about 27 miles per hour, and that the van came to rest in 227 yards 

and in 1 8 seconds. 

The object of the regulating valve was to obtain a uniform brake- 
block friction during the whole progress of the stop, and to give to this 
friction the highest admissible value, /. e., a value as nearly as possible 
equal to the adhesion of the wheels upon the rails, and therefore just 
short of that which could cause the wheels to skid. It will be seen 
from the diagrams that the rapidity of the stop varied according to the 
greater or less approach made towards the attainment of this object, the 
resistance of the valve itself being purposely altered during the progress 
of the experiments. 

The conditions for these stops were very favorable, and indicate an 
adhesion of the wheels upon the rails in excess of the average obtain- 
able ; which average, throughout 300 experiments, slightly exceeded 
.18 of the weight on the wheels. 

These experiments were made with the one van alone, without any 
carriages attached to it. Since making them the author has had the 
opportunity of making slip experiments on the Paris, Lyons & Medi- 
terranean Railway with twelve carriages attached to the van ( see 
page III). The average of seven stops reduced to 50 miles an hour 
was 203 yards, with only 63 per cent, of the weight of the train 
braked. If brakes had been applied to all the wheels of the train, as 
was the case in the experiments with the single van, the result would 
have been 128 yards from 50 miles an hour, or a very close approach 
to the best results obtained with a single vehicle. The author has not 
had time to analyse these latter experiments fully ; but he is able to 
state that they demonstrate that the stops which have been obtained 
with a single vehicle may also be obtained with a train of several 
vehicles. 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^""^'^^ 



Regulation of Pressure ?iecessary for a 
perfect Brake, 
The regulating valve here described is 
an outcome of the former experiments on this subject ; and is proposed 
for the purpose of preventing the sliding of the wheels on the rails. 
Some such device is a necessary adjunct to a perfect brake, because 
it is only by the prevention of skidding that the maximum of efficiency 
can be obtained ; whilst, in addition, skidding damages both wheels and 
rails, and increases the risk of accident. But the previous illustrations 
show that, however perfect any apparatus of this description may be, 
and however certainly it may act to prevent skidding, yet, owing to 
the very numerous conditions which aiFect the appHcation of brakes, 
it is necessary, if at the same time the maximum allowable friction is 
always to be exerted on the wheels so as to insure the best result in 
stopping, that the action of the apparatus should be capable of being 
regulated from time to time, so as to meet the varying conditions as to . 
adhesion, etc., of the hne on which it is travelling; unless indeed some 
arrangement could be made by which the actual adhesion at the moment 
could be brought into play to regulate the pressure. 

Momentum of Wheels due to Rotation, 

In dealing with this subject the author has not hitherto directed 
attention to the question of the influence of the rotating momentum of 
the wheels, but he now wishes to state what he has observed on this 
point. Usually there are in a train a certain number of vehicles braked 
and a certain number unbraked. When the brakes act on all the wheels, 
then the rotating momentum of the wheels does not add to the distance 
in stopping the train, because that momentum can be acted upon by the 
brakes directly, without in any way making use of the adhesion of the 
wheels upon the rails. It simply requires, therefore, an additional 
amount of brake-block pressure, and if a regulating valve be used, an 
increase in the resistance of the regulating valve to compensate for this 
rotating momentum. 

With the unbraked portion of a train, the rotating momentum of the 
wheels is an addition to the momentum due to the weight of the train 



^""^'^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



(including therein the actual weight of 

the wheels), which addition cannot be 

utiHzed for retardation ; and it therefore 

seems the more important that there should be brakes on every wheel 

of a train. 

Relation betzvee?i the Retardatio?i applied and the Weight of Train. 

The following Table XII. shows the distances run in stopping a train 
on a level from a speed of 50 miles per hour, with a retarding force 
varying from 5 to 30 per cent, of the total weight of the train : 

Table XII. — Retarding Forces and Stops. 



Retarding Force in 


Length of Stop 


Retarding Force in 


Length of Stop 


Proportion to 


from 


Proportion to 


from 


Weight of Train. 


50 Miles per Hour. 


Weight of Train. 


50 Miles per Hour. 


Per Cent. 


Yards. 


Per Cent. 


Yards. 


5 


555^4 


18 


15454 


6 


463 


19 


1461^ 


7 


369% 


20 


139 


8 


347^ 


21 


n^% 


9 


308% ^ 


22 


129% 


10 


^iiVz 


23 


120% 


II 


'^s^Yz 


24 


115% 


12 


^3iK 


25 


III 


13 


^^^% 


26 


107 


14 


i98>^ 


27 


103 


15 


185 


28 


99>^ 


16 


173% 


29 


95?^ 


17 


163^ 


30 


9^% 



If the brakes act upon every wheel, then a retardation of 10 per cent, 
of the load carried by each wheel — counting the rotating momentum 
as part of the weight — will stop a train in 2772/^ yards. If the brakes 
act upon only half the weight of a train, a retardation of 20 per cent, 
would have to be exerted upon the braked half to produce the same 
result. As already pointed out, 20 per cent, adhesion is rather above 
the average obtainable, while 24^ per cent, is the highest result ob- 
tained under the most favorable circumstances at any considerable 
speed, or except when sand was applied to wheels moving slowly. 

The above Table XII. should be carefully noted, for it will be seen 
that, even when brakes act upon all the wheels, 241^ per cent, re- 



GALTON- 
WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^"^^ 



tardation will only give 26 yards better 
result than 20 per cent., or 52 yards if 
only half the train be braked. If com- 
pared with 18 percent., the average adhesion obtainable, the advan- 
tage w^ill be only 41 yards for the train braked throughout, and 82 
yards for the train having brakes acting upon half of the w^eight. 

A consideration of this feature of the brake problem points out — i st, 
that the advantage to be gained by trying to obtain above 20 per cent, re- 
tardation on each w^heel is greatly overbalanced by the risk of skidding ; 
and 2d, that it is far easier and safer to make a stop in 250 yards from 50 

miles per hour with the whole 
train braked than with brakes 

Retardation 1 i i r r i 

per Carriage upou Only halt ot thc tram. 
All of this points to the fact 
that in arranging valves for 
regulating the brake-block 
friction care should be taken 
not to exceed a safe limit of 
adhesion ; for in the eiFort to 
get more work, less may be 
the result. 
Too much stress cannot be laid upon the importance of immediately 
applying the full pressure of the brake-blocks against the wheels, and of 
making the application simultaneous against all the wheels of the train ; 
for any loss of time seriously impairs the efficiency of the brakes in sev- 
eral ways, as has been already explained, independently of the actual 
increase of distance run in the stop. 

In illustration of this point, the diagrams shown in Figs. 43 and 44 
are added. Fig. 43 shows the result of an experiment made on 23d 
August, 1878, in which the application of the pressure was gradual, so 
as to represent the effect of a slowly-acting brake ; it furnished a 
diagram of a stop nearly identical with one of the best stops made by 
the Vacuum experimental train on the North Eastern Railway in 
October last. The curved lines S and F represent the speed and 
retardation obtained in the experiment ; and the straight lines S^ and 




^^s' ^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



pi the comparative results which would 
have been obtained if the fiill pressure had 
been applied at once, and if the conse- 
quent friction had been generated at once between the brake-blocks 
and wheels, and if this friction had been maintained at a uniform 
amount. In the latter case the stop would have been made in 125 
yards, instead of 287 yards, the actual distance. The straight line S^ 
shows a stop which might have been made in the same distance of 287 
yards, if the very moderate retardation indicated by the dotted line F^ 
had been appHed at once. It will be noticed that this stop is much 
better than the actual stop, though no shorter in distance, because at 
anv intermediate point the speed is much lower ; hence at 1 00 yards, 
for instance, the energy left in the train, as shown by the straight line 



Retardation 
per Carriage 
Lbs. 6000-1 




S2,is only three-fifths of that shown by the curved line S representing 
the actual stop. 

Fig. 44 illustrates the advantage of applying the brakes to every 
wheel of a train. 

The diagonal line A B indicates the stop which a train could make 
from 50 miles an hour with the retardation of .20, shown by the hori- 
zontal line C D, if apphed to every wheel in the train. The shaded 
area below^ C D shows the extra retardation consumed in overcoming 

1 the momentum of the braked wheels. 

I The diagonal line A E shows the stop which a train could make from 
the same speed with the same retardation of .20 applied to only half 

I the wheels and half the weight of the train, as indicated by the hori- 
zontal line F G. The shaded area below F G shows the extra retard- 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^""^'^^ 



ation consumed in overcoming the momen- 
tum of the braked wheels ; and the shaded 
area below A E shows the extra distance 
run by the train in consequence of the momentum of the unbraked 
wheels. 

The diagonal line A H shows the stop which a train could make 
from the same speed with the same retardation of .20 applied to only 
one-fourth of the wheels and one-fourth of the weight of the train, as 
indicated by the horizontal line J K. The thickness of the line J K and 
the diagonal shaded area below A H show respectively the extra retard- 
ation consumed in overcoming the momentum of the braked wheels, 
and the extra distance run by the train in consequence of the momen- 
tum of the unbraked wheels. 

Requirements of a perfect Brake. 

Having thus summed up the facts obtained from the experiments 
which he has made, the author will now add a few observations as to 
what appears to him still to be necessary in order to complete the 
investigation in a practical manner for the benefit of the railway com- 
panies and the public. 

The final solution of the vexed question of continuous brakes can 
only be brought about by a consideration of the subject in the light of a 
scientific and practical comparison between the various systems that 
have been brought into use. But before comparing these various 
brakes, it is necessary to consider what a perfect brake should accom- 
pHsh. 

A train, through the effort of the locomotive, slowly accumulates 
energy ; and for each ton of weight in the train the accumulated energy 
is equal to 120 foot-tons at 60 miles per hour, 53 foot-tons at 40 miles 
per hour, and i 3 foot-tons at 20 miles per hour. Thus for a train of 
fifteen vehicles, weighing 200 tons, the energy at 60 miles per hour is 
equal to 24,000 tons falling a distance of one foot ; or approximately to 
the energy of a shot from the 80-ton gun. 

After a train has attained the desired speed, the reasons for stoppingl 
it may be of two kinds : i st, at prearranged places for convenience ; J 



^""seQ? j^ir Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



and 2nd, for the prevention of accidents, 
or for mitigating the consequences if acci- 
dents are unavoidable. 

To stop a train for the first reason requires but a limited amount of 
force, which may be applied in any crude manner. 

For the prevendon of accidents, however, there is required :— 

(tf) The instantaneous appHcation of the greatest possible amount of 
retarding force. 

(^) The continuous action of this force until the energy of the 
train is destroyed. 

The retarding force now used in practice is that due to the friction 
resulting from the forcible application of metal or wood brake-blocks to 
the tires of the wheels ; this friction impedes the rotation of the wheels, 
and tends, through the adhesion of the wheels upon the rails, to destroy 
the energy stored in the train. The retarding force is therefore limited 
to the adhesion available between the wheels and rails. The greatest 
possible amount of retarding force can thus be obtained only by apply- 
ing brake-blocks to every wheel in tlie train, each block being pressed 
with sufficient force to produce a resistance to the rotation of the wheel 
just equal to the greatest possible friction between the wheel and the 
rail. This greatest possible friction occurs when the adhesion of the 
wheel to the rail is just about to be overcome by the superior effort of 
the brake-blocks, which effort, if further increased, immediately begins 
to stop the rotating movement of the wheel, and thus causes it to slide 
upon the rail. When a wheel slides upon the rail, its retarding effect 
is most materially lessened, as has been fully demonstrated above. 

The necessity for the instantaneous application of the maximum 
brake-block pressure throughout the train is so evident, that it is only 
necessary to call to mind that, at a speed which is frequently attained, 
namely 60 miles per hour, a train passes over 88 feet in each second. 

From the foregoing it will be seen that, in order to stop a train in 
the shortest possible distance, it is necessary : 

1st. That the brake-blocks should act upon every wheel in the train. 

2nd. That they should be applied with their full force in the least 
possible time. 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^^^ 



3rd. That the pressure upon them 
should be regulated according to speed 
and other circumstances, so that the fric- 
tion shall nearly equal, but never exceed, the adhesion of the wheels 
upon the rails. 

As it is solely for the object of preventing accidents, or of mitigating 
the consequences if accidents cannot be avoided, that the use of 
powerful brakes is urgently required, it becomes necessary to consider 
next the arrangements which this object necessitates. 

In the greater number of accidents the driver is the first to perceive 
danger, and he should therefore have the power of applying the brakes. 

The guards, however, who may be the first to discover the necessity 
for stopping, either when the driver fails to notice a signal at danger, 
or from other sufiicient cause, should also have power to stop the train, 
even against the eiForts of the driver. 

Should a train separate into two or more portions, the brakes should 
instantly act without the intervention of anyone, and should bring 
every portion of the train to a stand. 

If a carriage or even one pair of wheels should leave the rails, then 
also should the brakes be applied by the very act of the wheels leaving 
the rails. 

Should the brake apparatus of one or more carriages be destroyed 
after the commencement of the accident, while the speed yet remains 
considerable, the brakes upon the other carriages should not be 
rendered inefficient. 

It has been found that, although brakes are mostly intended for the 
prevention of accidents, they are also useful for ordinary stoppages, 
and effect a considerable saving of time. The use of continuous 
brakes moreover enables the number of guards and brakesmen in a 
train to be reduced. This use, however, becomes a source of danger, 
if from any cause the brakes fail to act when wanted ; hence the 
necessity for so constructing the brake apparatus that a failure of any 
essential part shall lead to the instant application of the brakes without 
the intervention of anyone : a principle which has been proved to be 
absolutely necessary in the working of the block system. 



^^^^^^ Air Brake Tests 



GALTON- 

WESTINGHOUSE 

TESTS 



As any one vehicle may become sepa- 
rated from the others, it follows that if 
the brake-blocks are to be applied by the 
separation of a train, each vehicle must have not only its own brake 
blocks, but also its own store of power to bring them into operation. 

As the speed of 60 miles per hour may be, and often is, attained 
by fast trains, the maximum force with which the brake-blocks can be 
pressed against the wheels of each vehicle in such trains should be at 
least one-and-three-quarter times the weight of the vehicle on those 
wheels ; and even for slower trains the effect of steep declivities must 
be considered, which is to add to the weight and momentum of the 
train to be retarded by the brakes, whilst it does not add to the 
adhesion of the wheels. 

The instantaneous and simultaneous application of the brakes to 
every wheel of a train would seem, so far as the author's experiments 
show, to be at present impossible ; but on a train of fifteen carriages 
the brakes can be fully appHed with an average delay of less than two 
seconds, and therefore the average time for the full application of the 
brakes may be fixed at two seconds. 

Accepting the foregoing propositions as indisputable, a perfect 
continuous brake should comply with the following conditions for the 
prevention of accidents : — 

1st. It should be fitted to act upon each wheel of the engine, 
tender, and every other vehicle in a train of any length. 

2nd. However brought into action, it should be capable of exerting 
upon the blocks of each pair of wheels, within two seconds, a force 
of twice, or at the very least one-and-three-quarter times, the load on 
those wheels. 

3rd. The brake-block pressure acting on each wheel should be so 
regulated that the friction between the brake-blocks and the wheel may 
always be limited so as not to exceed the adhesion between the wheel 
and the rail ; by which means it will produce the maximum effect at 
each moment of its application. 

4th. The brake-block pressure should be capable of being applied 
by engine-driver or by guards. 

LofC. 



GALTON- 

WESTINGHOUSE 

TESTS 



Air Brake Tests ^^^^^^^ 



5 th. The engine, tender, and vehicles 
should each carry their own store of brake 
power, which should be independent of 
the brake power on any other vehicle. 

6th. The brake-block pressure should be automatically apphed to 
every vehicle by the separation of the train into two or more parts ; and 
it should also be applied by a pair of wheels or a carriage leaving the rails. 

7th. The brake-block pressure should be automatically applied by 
such failure of the connections or appHances as would render it after- 
wards incapable of appHcation until the failure had been remedied. 

8 th. The brake-block pressure should be capable of application 
with any degree of force up to the maximum ; and it should be 
capable of continued action on inclines, or of repeated applications at 
short intervals at junctions and stations. 

In addition to these requirements, the questions of cost, durability, 
convenience in operation, and other essential points, will, of course, 
come under consideration. 

In preparing the way for a comparison of the various brakes now in 
use, one important point requires to be determined : — viz., how much 
brake force is actually required for each vehicle ? For convenience let 
us suppose, as is nearly the case, that each carriage weighs 9 tons or 
20,000 lbs. Then, according to requirement No. 2, a total brake- 
block pressure of at least 35,000 lbs. will be required ; and it would 
be preferable to have a still higher pressure. In practice the brake- 
blocks when out of action must be kept a certain distance away from 
the wheels, in order to prevent any liability to drag against them ; and 
this distance, after being once adjusted, gradually increases by the wear 
of the blocks, and often exceeds three-quarters of an inch ; while the 
springing of the brake gear under great strain also adds to the extent 
of movement required in the brake force before the blocks are fully 
applied. Thus it may be safely assumed that it requires not less than 
a pressure of 35,000 lbs. and a travel of one inch to apply the 
brakes upon each nine-ton vehicle ; or if the pressure were 3,500 lbs., 
acting at a leverage of 10 to i, there must be a travel of ten inches in 
order to produce the same result. 



^^^^^^^ Air Brake Tests 



GALTON 

WESTINGHOUSE 

TESTS 



Now, if this work has to be done 
with a piston working in a cylinder, 
or its equivalent, the cylinder must be of 
such a size that the area of the piston in square inches, multiplied by 
the stroke of the piston and by the pressure in lbs. per square inch, 
shall exceed 35,000. Thus in the above case, supposing the pressure 
to be 100 lbs. per sq. inch., a piston of 10 in. stroke, and of 35 sq. 
in. area, is the smallest that would be allowable. Any brake-cylinder 
having a less capacity than this will make it necessary that the blocks be 
kept closer to the wheels, or else that the brake-block pressure be reduced. 

It is obvious that each system of brakes could be made to operate 
upon the same kind of brake levers and blocks ; and therefore, in 
comparing the various systems of brakes, they ought to be applied to 
like vehicles, and to be made of such dimensions as to give the same 
total brake power. 

The author had originally intended to continue these experiments 
on brakes, so as to ascertain the retarding power of the different kinds 
of continuous brakes now in use, on trains under similar conditions, of 
equal weight, and running at the same speed. He had the oppor- 
tunity, through the courtesy of the North Eastern Railway Company, 
of making a few comparative experiments upon the Westinghouse 
Automatic Air Brake, and the Vacuum Brake. These experiments, 
although highly interesting as far as they went, left many points 
unsolved. But they went sufficiently far to show that, in the present 
stage of the brake question, a series of experiments which touch upon 
the interests of rival inventors, who have invested large sums of money 
in their respective enterprises, cannot be effectually carried on by a 
private individual. It does not seem probable that the different 
railway companies will arrive 'at an understanding to initiate and carry 
on joint experiments for ascertaining the performances of the various 
kinds of continuous brakes. The only way, therefore, by which an 
independent enquiry could be made would be by a Government 
Commission, appointed on the principle of the Commission which 
enquired into the application of iron to railway structures in 1849, 
viz., to state facts and lay down principles. 



THE PARIS AND LYONS RAILWAY TESTS. 

The following paper was read before the Institution of Mechanical 
Engineers at same meeting when Capt. Galton read his third paper on 
the effect of brakes upon railway trains (April 24, 1879), ^^^ 
relates to some tests made by the Paris & Lyons Railway in April, 
1879, ^^^ reported by the chief engineer of that road, M. Marie. 

ON RECENT BRAKE EXPERIMENTS UPON THE 
LYONS RAILWAY. 



By M. GEORGE MARl£, of Paris. 

I. Particulars of Apparatus. 
The Paris and Lyons Railway has lately experimented on two 
trains, one fitted with the Westinghouse brake, and one with the 
Smith Vacuum brake. Both trains were alike, and were composed as 
follows : — 



Vehicle. 


Axles. 


Load per Axle. 
Lbs. 


Total Load. 
Lbs. 


I engine, 4 axles (in working 
order) 


r 2 driving axles, together 
\ 2 loose axles, together 


44,100/ 


99,225 


I tender, 3 axles (in working 
order) , 


r 1st axle, with brake . 
< 2d axle, without brake . 
(3d axle, with brake 


25,357) 
17,640 - 

25,357. 


68,354 


25 carriages (empty), 3 axles . 


r ist axle, with brake . . 
- 2d axle, without brake . 
3d axle, with brake 


7,276) 

6,394 \ 
7,276 J 


20,946 


Same carriages (loaded), 3 
axles 


r I St axle, with brake 

^ 2d axle, without brake . 

(3d axle, with brake . 


8,676^ 

7,594 \ 
8,676) 


24,946 



The engine is not fitted with any brake, except the " Le Chatelier '' 
counterpressure apparatus. This apparatus,* as improved by the chief 

^ See Proceedings 1870, p. 21. 



^^^^^^-^ Air Brake Tests 



PARIS AND 
LYONS RAILWAY 
TESTS 



engineer, M. Marie, has worked excel- 
lently for fifteen years, in daily use, both 
in all stops at stations, and also on long 
inclines. Some remarks will be made hereafter on the power of the 
counterpressure apparatus compared with a brake on the driving wheels. 
Each carriage had only two axles fitted with brakes, the middle axle 
being left free ; the fear of the complication arising from a six -wheel 
brake was the reason of this ; but, in order to have power enough, a 
great brake-block pressure was provided. The following table shows 
the brake-block pressure on every axle of the train. The pressure in 
the brake cylinder is here supposed to be 37 lbs. per square inch ; and 
the vacuum in the '* Hardy" sack to be 16 inches of mercury. 
These pressures must be considered as an average of the ordinary 
pressures in practice. 



Air 
Pressure, 

or 
Vacuum. 







Total 


Load on 


Pressure 


Pressure 


Brake- 


Rail 


on the 


on the 


block 


for each 


Outside 


Inside 


Pressure 


Braked 


Blocks. 


Blocks. 


per Axle. 


Axle. 



Ratio of 
Brake- 
block 
Pressure 
to Load. 



Westinghouse. 
Tender ( ist and 3rd axle) 
Empty carriage (ist and 
3rd axle braked) 



Lbs. per 
Sq. in^ 

37 
37 
37 



Lbs. 

6,666 
4,191 
4,191 



Lbs. 

10,016 

6,303 
6,303 



Lbs. 
16,682 
10,494 
10,494 



Lbs. 

25,357 
7,276 
8,676 



Per Cent. 
66 

144 



Vacuum. 
Tender (ist and 3rd axle) 
Empty carriage (ist and 
3rd axle braked) 



Inches 

Vacuum. 

16 

16 

16 



Lbs. 

15,020 

8,342 

8,342 



Lbs. 

9,874 

5,045 
5,045 



Lbs. 
24,894 

13,387 
13,387 



Lbs. 

25,357 
7,276 
8,676 



Per Cent. 

98 

184 

154 



The pressures were not large enough to skid the wheels at high 
speeds, but at low speeds the wheels were skidded, especially with 
empty carriages. This latter is no real disadvantage, because in ordi- 
nary stops the driver can moderate the brake power. Mr. Westing- 
house, however, in order to avoid skidding under any circumstances, 
fitted, as a trial, twelve carriages with reducing valves, operated by the 
friction of the brake-blocks. The arrangement of these was the same 
as is given in Captain Galton's paper (Figs. 35 to 37, pages 83 
and 85). 

It will be seen that, in the case of the Westinghouse brake, the pressure 
on the outside blocks (or those furthest from the centre of the vehicle) 



PARIS AND 
LYONS RAILWAY 
TESTS 



Air Brake Tests ^"^''""^ 



is less than on the inside blocks, which ar- 
rangement has the disadvantage of creat- 
ing a strain on the horn plates equal to 
the difference of these two pressures ; but has, on the other hand, the 
following advantage. When the brake is applied to the whole train, each 
carriage is subject to a strain, created by inertia, equal to the mass of 
the carriage, multiplied by the rate of retardation of the train. This 
strain equals, on an average, about -^-^ of the weight of the carriage ; it 
acts as a forward push applied to the centre of gravity of the carriage, 
and changes the distribution of the weight on the axles, the front axle 
becoming more loaded than usual, and the rear axle less. This is an 
important matter, because the springs of the carriages are sometimes 
damaged by the action of this extra load on the front axle. Mr. 
Westinghouse has therefore arranged his brake gear in such a way as to 
create a vertical force, counteracting partially this extra load, by giving 
more pressure on the inside blocks than on the outside ones. These 
pressures being different, the frictional resistances are difi^erent also, and 
the difference forms a vertical force acting upwards on the springs of 
the front axle, thereby balancing so far the action of inertia. 

In the case of the Vacuum brake gear the pressure on the outside 
blocks is greater than on the inside ones, which causes a reverse action, so 
as to add to the extra load created by inertia upon the front axle. From 
this it follows that the compression of the front springs is somewhat 
greater in the case of the Vacuum than of the Westinghouse brake. In 
the Westinghouse brake gear this difference of pressures is equal to 
6303 — 41 9 1 = 2112 lbs. for each axle ; and the difference of fric- 
tional resistances is equal to = 422 lbs. (with a coefficient of 

friction of .20). In the Vacuum brake gear the difference of pres- 
sures is equal to 8342 — 5045 = 3297 lbs.; the difference of resist- 
ances is therefore equal to =659 lbs. Thus with the Westing- 
house brake there is a counteracting force, as described, of 420 lbs. ; 
whilst with the Vacuum brake there is an augmenting force of 660 lbs. 
From this cause the front springs are more loaded with the Vacuum brake 
than with the Westinghouse ; and this strain is still greater towards the 



^^^^^^-^ Air Brake Tests 



PARIS AND 
LYONS RAILWAY 
TESTS 



end of the stop, because the friction in- 
creases considerably at that moment, as 
may be seen in the friction diagrams of the 
Brighton experiments. The practical result of this during the trials 
was that in the Westinghouse train only one front spring was flattened 
down, while in the Vacuum train all were. The author does not 
understand the object of the latter type of brake gear, which is gener- 
ally applied with the Smith brake, and is also extensively used by the 
Great Northern Railway in England. 

It is impossible to avoid entirely the above-mentioned strain on the 
horn plates ; and in addition, the horizontal force retarding the train 
must produce another strain on the horn plates, which is equal to 
— ^1^= 2,099 ^^' P^^ "^^^ ^^^ ^^ Westinghouse brake. Thus with 
this brake the horn plates of the front axle have to support two strains 
in opposite directions, one equal to the difference of the brake-block 
pressures, or 2,1 12 lbs., and one equal to the retarding force, or 2,099 
lbs. ; the resultant strain is therefore only 2,112 — 2,099= ^3 ^^* 
But on the horn plates of the rear axle the forces act in the same 
direction, and therefore the total strain is equal to 2,112 + 2,099= 
4,211 lbs. From this point of view it would be better to have the 
same brake-block pressures on both sides of the wheel, so that the 
strain on the horn plates should be only 2,099 lbs. at each end of the 
carriage ; the advantage of unequal pressures, as above described, would 
then be lost, but still the author would prefer this arrangement. 

The stroke of the piston, both in the air cylinders and in the Hardy 
sacks, was calculated so as to have a theoretical clearance of ^ inch 
between the blocks and the wheels, when the brakes were off. In 
the trials, the distance between each block and its wheel was ^ inch 
when the brakes were off; the difference, ^ inch, was allowed for 
the bending and springing of the brake gear. 

II. Practical Working of the two Brakes. 

Trains fitted with a Westinghouse and with a Vacuum brake have 
been running for two months from Paris to Montereau (49 miles) and 



PARIS AND 
LYONS RAILWAY 
TESTS 



Air Brake Tests ^""^''"^ 



back, and from Paris to Corbeil (20 miles) 
and back. The Westinghouse brake has 
worked very well when there has been no 
leakage in the pipes, but it is necessary to watch all the apparatus with 
the greatest attention ; sometimes one or two of the triple valves get 
out of order, and disturb the action of the brake, causing very severe 
shocks to the couplings, especially with trains of twenty-four carriages. 
The Vacuum train has also given good results, but the couplings are 
often damaged ; the operation of putting the couplings together is 
much more difficult than with the Westinghouse brake. With both 
brakes the passengers generally feel no shock, provided the driver 
releases the brake a few yards before the end of the stop. The 
practical trial of both these trains has as yet been too short for giving 



any 



definite conclusion. 



III. Experiments of the ist and 2nd April. 



The London, Brighton and South Coast Railway, as represented 
by their general manager, Mr. Knight, and locomotive superintendent, 
Mr. Stroudley, sent over to the Lyons Railway the experimental van 
already used during Captain Douglas Galton's experiments at Brighton 
and York. The author takes this opportunity of thanking those 
gentlemen, and also Captain Galton, Mr. Westinghouse, and Mr. 
Kapteyn, of Paris, for their assistance in these experiments. A 
description of the apparatus has already been given in Captain Galton' s 
papers on the subject. In the present experiments two diagrams only 
were taken for each stop ; first, the diagram from the speed indicator, 
giving the square of the speed of the train at each point of the 
distance run ; second, the diagram giving the brake-block pressure on 
the front axle of the van. This axle had been fitted with a Westing- 
house brake and with a Vacuum brake, which could be used independ- 
ently. In Captain Galton' s experiments the abscissae were made 
proportional to the time, the recording cylinders being connected with 
a water clock, and so turned round with a uniform speed. In the 
Lyons experiments, the abscissae were made proportional to the 
distance run by the train ; for this purpose the recording cylinders were 



^^^^^^^ Air Brake Tests 



PARIS AND 
LYONS RAILWAY 
TESTS 



connected with the rear axle of the van ; 
that axle had no brake, and therefore gave 
a distance exactly proportional to the dis- 
tance run by the train. When the train was run without brakes being 
applied, this connection between the recording cylinders and the rear axle 
was broken ; when the driver applied the brake, the connection was 
immediately and automatically established by means of friction gearing, 
actuated by electricity. The brake-block pressure is exactly propor- 
tional to the air pressure in the brake cylinder, or to the vacuum in the 
Hardy sack. On the diagram. Fig. 45, are two scales, adapted for 
measuring the air pressure and the vacuum from the diagram of the 
brake-block pressures. The lines marked W denote the Westinghouse 
brake, and the lines marked V the Vacuum. The full lines show 
the speeds, and the dotted lines give the air pressure in the brake 
cylinder in lbs. per square inch, or the vacuum in the Hardy sack in 
inches of mercury. It will be seen that in Captain Galton's diagrams 
the lines of speed are convex towards the base line, while in these 
they are concave ; the reasouLof this is the difference already explained 
between the abscissae used in each case. 

On 1st April experiments were made with the Vacuum brake. ^ 
From Paris to Montargis (73 miles) the train was composed of 1 
engine, tender, ordinary van, experimental van, twenty-two car- | S 
riages. From Montargis to Paris the train was much shorter, com- 5- | 
prising engine, tender, ordinary van, experimental van, six carriages. ^?l 
On 2nd April the same 
experiments were MUes 

. ^-.^ p. hour ^■>'>^ 

made with the West- '" ' ' 
inghouse brake, and 
with the same num- 
ber of vehicles. A 
great many diagrams 
were taken, from 
which five are chosen, 

representing the average of all the cases. By the aid of those 
diagrams. Figs. 45 to 49, the results may now be described. 



Fig. 45 

Twenty -four Carriages. 




five 



PARIS AND 
LYONS RAILWAY 
TESTS 



Air Brake Tests ''"^''"^ 



Fig. 45 represents two stops with 
twenty-four carriages (including the two 
vans), one stop with the Westinghouse, 

the other with the Vacuum brake. The weights of the trains were 

as follows : — 





Weight on Unbraked 
Wheels. 

Lbs. 


Weight on Braked 
Wheels. 

Lbs. 


Engine 


99,225 

17,640 

147,062 

10,000 




Tender 

Carriages and van, empty .... 
Experimental van, loaded .... 


50j7H 

334,696 

10,400 


Total 


273,927 


395,810 



65 Miles per hour 



Pig. 46 

Eight Carriages, 
with Counterpressure. 



sJT 



Miles 
per hour 
40 



20 
-10 



) 300 

Fig. 47 

Eight Carriages, 
without Counterpressure. 



500 Yards 600 



^"^^^^^ Air Brake Tests 



PARIS AND 
LYONS RAILWAY 
TESTS 



Total weight of the train, 669,737 
lbs.; proportion on braked wheels, 59 
per cent. 

In order to be exact there ought to be added to the total weight of 
the train the weight of all the unbraked wheels, because the brake is 
obliged to destroy the rotating momentum of those wheels. But, as 
this error is very small, and the same for both brakes, it has not been 
taken into consideration in the calculations. The results of Fig. 45 are 
therefore as follows : — 



Brake. 


Speed of 
Train. 

Miles per 
Hour. 


Length of 
Stop. 
Yards. 


Duration 
of Stop. 
Seconds. 


Gradient. 


State of Rail. 


Westinghouse 
Vacuum . 


37 
35 


217 
280 




r Rising 1 
\ I in 200 j 
Level 


Rather Wet. 



The diagram shows the variation of the air pressure in the brake 
cylinder, and of the vacuum in the Hardy sack. The full pressure 
was almost instantaneously applied with the Westinghouse brake ; its 
variation shows the action of the regulating valve in the van. The 
vacuum increases slowly, and reaches 13^ inches at the end of the stop ; 
in the rear of the train the vacuum was no doubt created more slowly 
still, but no experiments with recording apparatus were made to ascer- 
tain this point. 

This trial was the most unfavorable for the Vacuum brake, the 
number of carriages being large and the speed small. 

Figs. 46 and 47 show a few stops with the return train of eight car- 
riages (including the two vans). 

The weights of the train were as follows : 





Weight on Unbraked 
Wheels. 

Lbs. 


Weight on Braked 
Wheels. 

Lbs. 


Engine 

Tender 

Seven carriages, empty 

Experimental van, loaded .... 


99,225 
17,640 

44,758 
10,000 


50,714 

101,864 

10,400 


Total . , .' 


171,623 


162,978 



PARIS AND 
LYONS RAILWAY 
TESTS 



Air Brake Tests ^"^'"'^ 

Total weight of the train, 334,601 
lbs. ; proportion on braked wheels, 49 
per cent. 



The particulars of the stops were as follows : 



Brake. 


Speed. 

Miles per 

Hour. 


Length of 
Stop. 
Yards. 


Duration 
of Stop. 
Seconds. 


Gradient. 


State of Rail. 


Westinghouse, Fig. 46 . 
Vacuum, Fig. 46 




570 


32 
37 


j Falling ) 

( I in 200 [ 

do. 


Dry. 
Quite wet. 


Westinghouse, Fig. 47 . 
Vacuum, Fig. 47 . 


37 

37 


203 
213 


16K 
19K 


( Falling ) 

( I in 1000 ) 

do. 


Dry. 
Quite wet. 



The two first stops ( Fig. 46 ) were made with the aid of the 
counterpressure of the engine ; the two last (Fig. 47) were made with- 
out counterpressure. The line C of Fig. 47 shows a stop made with 
counterpressure alone. 

As may be seen, the results are not very different, the trains having 
very few carriages. 

Fig. 48 

Westinghouse Brake 
worked from Rear Van. 



Pig. 49 

Pressure 

Slip Stop, Westinghouse ^^g^-Jf^, 




References 



I PF'= Westinghouse Brake 
t Speed 



V = Vacuum Brake 
Pressure or Vacuum 



Fig. 48 shows a stop obtained with the Westinghouse brake, worked 
from the rear van of the train. The following are the particulars : 
Speed, 40 miles per hour. 
Length of stop, 248 yards. 
Time, not observed. 
Gradient, level. 
Rail, dry. 



^""s"''' Air Brake Tests 



PARIS AND 
LYONS RAILWAY 
TESTS 



. The train had exactly the same com- 
position as that in the experiments with 
eight vehicles ; the regulator of the engine 
was kept full open until the train had come to rest. 

Fig. 49 shows a slip experiment with the Westinghouse 
brake. The part of the train which was slipped was com- 
posed of the experimental van and six carriages. The weights were 
as follows : 





Weight on Unbraked 

Wheels. 

Lbs. 


Weight on Braked 

Wheels. 

Lbs. 


Experimental van, loaded 

Six carriages, empty 


10,000 
38,364 


10,400 

87,312 


Total 


48,364 


97,712 



Total w^eight of the train, 146,076 lbs.; proportion on braked 
w^heels, 6^] per cent. 

The following are the particulars of the stop, which was a very 
good one : 

Speed, 41 miles per hour. 

Length of stop, 150 yards. 

Duration of stop, 12^ seconds. 

Gradient, level. 

Rail, dry. 

In this stop, as in the last, the recording instruments were started by 
the air pressure in the brake cylinder of the van, instead of being started 
by electricity as before. There was in consequence a slight loss of 
time, especially in the stop from the rear van. Fig. 48. 



IV. Comparison of the Retarding Forces in Different Stops. 

It is easy to compare stops with each other, although the speed, the 
gradient, and the proportion of weight on braked wheels be different in 
each. This can be done by calculating the retarding forces of the 
brake for each stop. 

If we called S the speed in miles per hour, / the length of the stop 



PARIS AND 
LYONS RAILWAY 
TESTS 



Air Brake Tests ^"^'''^ 

in yards, and W the weight of the 
train, then the retarding force F is 
given by the formula : 
F S2 

^=o.oii xA..* 

The diagrams give w^ith precision the values of S and /in each stop; 
hence it is easy to calculate the retarding force in each case. On the 
diagrams, the ordinates are proportional to the square of the speed, and 
the abscissae proportional to the length of stop ; thus, the average 
retarding force is proportional to the inclination of the straight line 
drawn between the extremities of the speed curve, while the exact 
retarding force at each point of the diagram is given by the inchnation 
of the tangent to the curve at that point. We can now compare stops 
made at different speeds. 

To compare stops made on different gradients, we must add the 

F . 

gradient to — , with the sign -f if it is falling, and with the sign — 

F^ . 
if it is rising. We will call —- this corrected retarding force. 

To compare stops in which the percentage of weight on braked wheels 

is different, let A be that percentage. If we multiply — by — , we 

F^/ . 

have a number -— , which would be the retarding force for a train 

stopped on a level line with the whole weight of the train braked. 

p// 
If we calculate the values of — for all the stops, the numbers 

obtained compare exactly the powers of the brakes, whatever may be 



■^ Let s be the speed of the train in yards per second, t the number of seconds of the 
stop, and / the length of the stop in yards. Then, if we suppose the retardation k to be 

1 I ^2 J ^2 

constant during the stop, 5 =: kt. Also / =: —ktz-^ hence / =z—k — — = : thus, if 

2 2 /^'-^ 2 ^ 

we take the value of k from this formula, we have k = — — • 

2/ 

Now let g be the acceleration of gravity in yards per second j let F be the retarding 

force of the brake in the whole train, and let W be the total weight of the train. 

Then, because forces are proportional to their accelerations, we have : 

F k s^ S2 

-—=—=—- = 0.011 X-y- 
W ^ 2/^ / 



^""^'"^ Air Brake Tests 

the circumstances of the stop. The 
following Table gives this comparison 
for the present diagrams : — 



PARIS AND 
LYONS RAILWAY 
TESTS 

















Si£^.. 


p// 




a. 




F 
W 


Gradient. 




F' 
W 


Percenta 

of Weig 

on Brak 

WheeL 


w 

Power 
of the 
Brake. 


Westinghouse, alone : 24 








j Rising 
\ I in 200 


\ 








carriages, Fig. i . 


37 


217 


0.075 


0.070 


59 


0.I19 


Vacuum, alone : 24 car- 














riages. Fig. I 


35 


280 


0.057 


Level 




0.057 


59 


0.096 


Westinghouse, alone : Slip 


















experiment. Fig 5 


41 


150 


0.130 


do. 




0.130 


67 


0.200 


Westinghouse, alone: Brake 


















from rear van. Fig. 4 


40 


248 


0.080 


do. 




0.080 


49 


0.160 


Westinghouse, alone: 8 car- 








j Falling 
( I in 1000 










nages. Fig. 3 . . 


37 


203 


0.085 


0.086 


49 


0.170 


Vacuum, alone: 8 carriages. 


















Fig. 3 . . . . 


37 


213 


0.080 


do. 




0.081 


49 


0.160 


Counterpressure, alone : 8 


















carriages. Fig. 3 . . 


35 


sH 


0.024 


Level. 




0.024 


16 


0.150 



The stops in Fig. 46 have not been worked out because they were 

made with the brake and the counterpressure together. 

F 

The retarding force — - ought to be diminished by the ordinary 

resistances of the train, that is to say, by 0.003 ^^ 0.008. This makes 
but a small difference when the proportion of braked weight is large ; 
but in the last stop, with counterpressure alone, this correction gives to 

W 



a value o. 125 instead of o. i 50. 



V. General Conclusions. 



F// 



We have seen that the value of — is the best comparison for the 
power of the brakes in all cases. Now with the Westinghouse brake 

— : is generally between 0.120 and 0.200, w^hile with the Vacuum 

p// 
brake — is generally between o. 100 and o. 160. This shows a slight 

advantage for the Westinghouse brake, but it must be remarked that the 
rail was better during the trial of the Westinghouse than of the Vacuum 



PARIS AND 
LYONS RAILWAY 
TESTS 



Air Brake Tests ^""^'"'^ 

brake. We have also seen that the value 
of ^ for the counterpressure is 0.125, 
while the average of the Westinghouse 
trials gives o. 160, with a brake-block pressure of about 140 per cent, of 
the weight on the braked wheels. Thus the counterpressure on the driv- 
ing wheels is as powerful as a Westinghouse brake which has a pressure 

of 140 X -7^ =109 per cent, of the weight on those wheels. It may 

be suggested that in a quick stop the time occupied in reversing the 
steam on the engine must practically diminish the power of the counter- 
pressure ; this is true, but on the other hand the brake-block pressure 
on the driving wheels with the Westinghouse brake is generally less 
than 109 per cent., and often less than 80 per cent. Thus the counter- 
pressure is as powerful as the Westinghouse brakes generally in use on 
the driving wheels. On the Lyons Railway the drivers have been 
accustomed to the counterpressure for fifteen years ; hence, whatever 
may be the final choice of brake, the Company will put no brake on 
the driving wheels. 

The diagrams show that the Westinghouse brake comes on almost 
instantly over the whole train ; it is not the same with the Vacuum 
brake. There the brake goes on first upon the front carriages, and the 
buffers are consequently compressed ; afterwards the carriages all become 
braked, and the buffers return to their first position, but not without 
oscillations which are serious, both for the passengers and for the couplings 
themselves. In the Westinghouse brake this action is much slighter. 

In all the trials the wheels skidded only at a very low speed ; hence 
the regulating valves did not show any great advantage in the length of 
the stop. They save the tires by preventing the wheels from skidding, 
and they save also the springs of the carriages by diminishing the shock 
felt at the last moment of a stop. Though a very ingenious improve- 
ment, yet, if the driver can really graduate the strength of the brake, 
it may be doubtful whether they are necessary in continuous brakes ; 
thus one more complication may, perhaps, be avoided. 

The Lyons Railway had never previously had an accident caused by 
the breaking of draw-bars in a passenger train, but several were broken 



^""^'"'^ Air Brake Tests 



PARIS AND 
LYONS RAILWAY 
TESTS 



in the trains fitted with the Westinghouse 
and Vacuum brakes. Thus, if there has 
been no such breaking of draw-bars in 
past times, yet these are almost sure to occur frequently with the use of 
continuous brakes : and as there are on the railway several very steep 
gradients, it would seem that a non-automatic brake would on this Hne 
at least be dangerous, unless, to avoid accidents, the ordinary hand 
brakes are still kept in use on the trains. 

The arrangements of the Westinghouse brake are certainly rather 
complicated, especially the air pump and the triple valves. As regards 
the pump, the author thinks that it would be difficult to make an air 
pump more simple and at the same time able to satisfy all conditions. 
And as regards the triple valve, he thinks it is impossible to simplify it 
without losing one of the two following advantages — the quickness of 
application of the brake, or its graduation in the stops. It might, 
however, be rendered less delicate by making it larger and stronger. 
All the other parts of the brake are quite satisfactory. 

All the parts of the Vacuum brake are very simple and strong, but 
the leather of the Hardy sack seems to be a bad material for practical 
work. Some arrangement of metallic pistons and cylinders would seem 
preferable, but practice alone can decide this question. The arrange- 
ment of the brake gear is not quite satisfactory, but it would be easy to 
improve it. 

The above opinions must be taken as those of the author alone, and 
as requiring to be checked by longer experience. Both brakes will be 
tried on long inclines, and a uniform speed maintained with them if 
possible. Until these trials have taken place, no decisive opinion can 
be given by the railway company. 



THE BURLINGTON BRAKE TRIALS. 

These trials were carried on at the instance of the Master Car 
Builders' Association, whose Committee on Automatic Freight Car 
Brakes were directly in charge. 

Two series were run, the first in 1886 and the second during the 
year following. In the latter year this Committee made a report to the 
meeting of the M. C. B. Association, at St. Paul, Minn., on June 15th, 
1 6 th, and 17 th, which contained a full detailed description of the tests, 
and the following pages are taken from it : 

Programme of General Tests, 1886* 

1. Fifty-car trains on down grade 53 feet per mile, running for- 
ward, quick stops. 

a. All cars loaded, 30 and 20 miles per hour. 

b. All cars empty, 40 and 20 miles per hour. 

c. Cars mixed (see below), 40 and 20 miles per hour. 

Note. — Half the cars to be loaded and half empty, 75 per cent, of the latter to 
be on front half of train. During these tests, the rapidity with which the train gets 
away after a stop will be noted, the time being taken from stop to start. 

2. Fifty-car trains on level, running forward, quick stops. 
Same as tests on grade, except that trials are on level. 

Note. — In order to attain a speed of 40 miles per hour, pushers or double-headers 
will be used, at option of brake company. 

3. A train of fifty (50) half loaded and half empty cars, 75 per 
cent, of the latter to be on front half of train, to be let down a grade of 
53 ft. per mile 3 miles long. Speed of 20 miles per hour at top of grade 
to be reduced to i 5 miles per hour and maintained without material 
variation all down the grade. 

4. Twenty-five (25) car trains. Twelve (12) cars to be loaded, 
and thirteen (13) empty, about 75 per cent, of empties being on the 
front half of train. Tests to be made on a down grade of 53 ft. per 
mile, running forward at speeds of 40 and 20 miles per hour. 

5. Similar trains to above. Tests to be made on level at 40 and 
20 miles per hour. 



^""^'"'^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



6. Similar trains to above. Tests 
to be made ascending grade of 53 ft. 
per mile, engine in front of train pull- 
ing. Speed, about 1 2 miles per hour. 

7. Engine tests. Engine and dynamometer car. Two stops 
on level track at 20 and 40 miles per hour, and two stops on 53 ft. 
grade at 20 and 40 miles per hour. 

8. Hand-brake stops with engine and tender power brakes ; 25 
mixed car train. Two stops on level track at 20 and 40 miles per 
hour, and two stops on 5 3 -ft. grade at 20 and 40 miles per hour. 

9. Train resistance test ; 25 mixed car train. 

(i.) To pass No. I stop-post at 20 miles per hour, letting the 
train drift till it stops, no brakes being applied. 

(2.) To pass No. 3 stop-post at 5 miles per hour, letting the 
train drift until No. 4 post is reached, at which point the accelerated 
speed shall be recorded and the train stopped. 

10. Empty 50-car train; the 30 forward cars to have automatic 
brakes, and the rear 20 cars Xo be without automatic brakes. Three 
stops each at 20 and 40 miles per hour on the levels and 20 and 40 
miles per hour on the 5 3 -foot grade. 

Special Tests, 

1 . Twenty-five-car trains. Half the cars to be loaded and half 
empty, 75 per cent, of the empty cars being on the front half of the 
train. Tests on the level. Trains to be broken in two near the 
center. Speeds 40 and 20 miles per hour. After the train is broken 
in two, any assistance necessary will be rendered only by a brakeman, 
who shall be riding at the rear of the train when the breakaway occurs. 

Note. — In all the above tests, all the cars in a train are fitted with the same auto- 
matic brake. 

2. Similar trains as above as regards number and loads of cars. 
One-half of the cars to be equipped with the same automatic brake, and 
the other half with hand brakes only. Three cars with hand brakes 
only next tender, then three with train brake, and so on. Tests on 
the level. Speeds, 30 and 20 miles per hour. 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^'"^ 



3. Twenty-five (25) car mixed 
trains with the same train brake on twelve 
(12) cars next tender. The rear 13 

cars to have hand brakes only. Speeds, 40 and 20 miles per hour. 

Tests to be on level. 

4. Fifty-car trains. Trains to be composed in equal proportions 
of diiFerent train brakes that will operate together. Half of the cars 
empty and half loaded — about 75 per cent, of the empty cars in front 
of train. 

5. Consolidation engine train test ; 50 loaded car train. Two 
stops each to be made at stop-posts Nos. i, 2, 3 and 4 at 20, 30, 20 
and 30 miles per hour respectively. 

[Note. — General tests 4 and 6 were erased at a joint meeting held at Burlington 
prior to the tests, and Nos. 7, 8, 9 and 10 and Special test No. 5 were added. Special 
tests Nos. 2, 4 and 5 were inserted in the interests of the buffer brakes.] 

A dynamometer car to be placed in the front end of each train, 
with complete recording mechanism. In the middle box car of each 
train a portable apparatus to be placed for recording diagrams ; 
showing, 1st, a strain line in pounds exerted on the brake lever during 
the stops, and, 2d, a speed line in miles per hour during each stop. 
An electric signal to be arranged for communication between the front 
and rear ends of the train. 

The ground selected for the trials was a stretch of track commencing 
eight miles west of Burlington, the Chicago, Burlington & Quincy 
shops being located midway in the course. The first 5 miles, it will 
be seen by reference to plate I, is a level stretch of single track, on 
which is located stops Nos. i and 2, a distance of 2.858 miles being 
between the stops. The last 3 miles of the course is double-tracked, 
something over 2 miles of it being on a down grade of 53 ft. to the 
mile. On this we find stops 3 and 4, — No. 3 being 2.21 miles 
from No. 2, and No. 4, 1.242 miles from No. 3. The natural 
advantages of such a course soon became apparent. Without in any 
way interfering with the regular traffic of the road, the Committee were 
enabled under favorable circumstances to make five trips a day, equal 
to an 80-miles' run, and to dispose of 20 of the stops. 



Profile and Plan of track where the Burlington Trials were Held. 



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^""^'''^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



The companies that entered the 1886 
contest were : 

1 . The Westinghouse Automatic Brake 
Company of Pittsburg. Its equipment was attached to 50 Chicago, 
BurHngton & Quincy standard 40,000-lbs. box cars. 

2. The Eames Vacuum Brake Company of Boston, Mass. Its 
appHances were applied to 50 40,000-lbs. cars of the IndianapoHs, 
Decatur & Springfield Railroad. 

3. The American Brake Company of St. Louis, Mo., with 50 
standard 40,000-lbs. cars o'i the St. Louis & San Francisco Railroad. 

4. The Widdifield & Button Brake Company of Uxbridge, Ont., 
Canada, with 56 cars of 40,000 lbs. capacity of the Lehigh Valley 
Railroad. 

5. The Rote Brake Company of Mansfield, O., with 50 standard 
40,000-lbs. cars of the Chicago, Rock Island & Pacific Railroad. 

These five competitors may be classed as representing two types of 
brakes : the Continuous or Air brakes being represented by the Westing- 
house and the Eames, and -the Independent or Buffer brakes by the 
American, the Widdifield & Button, and the Rote. The general 
features of the brakes may be obtained fiom Figs. 58, 59, and 60. 
The cars were all of the eight- wheel type. 

The Westinghouse Brake, 

The Westinghouse automatic freight-car brake, as used in the 
contest of 1886, is illustrated as follows : 

Fig. 50 shows the triple valve, reservoir, and brake-cylinder. The 
triple valve is shown in section in Fig. 5 1 , and thus described : 

The piston, 5, works in the chamber B, and carries with it 
a shde valve, 6. Air enters from the main pipe through the four- way 
cock into the drain-cup A, and passes to the chauiber B, forcing the 
piston horizontally, and uncovering the small feed-groove in the side of 
the chamber, which permits air to flow past the piston into the auxiliary 
reservoir, while, at the same time, there is an open communication 
from the brake-cylinder to the atmosphere, through the passages d, e, 
/, and g. 



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^^^^^^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



^ To apply the brakes with their full 
force, the compressed air in the main 
brake-pipe is allowed to escape, when the 
greater pressure in the' auxiliary reservoir moves the piston 5 beyond 
the feed-groove, thus preventing the return of air from the reservoir to 
the brake-pipe. As the piston travels, it moves with it the slide valve 6, 
so as to permit air to flow directly from the auxiliary reservoir into the 
brake-cylinder, which forces the pistons out and applies the brakes. 
The brakes are released by again admitting pressure into the main brake- 
pipe from the main reservoir, which pressure, being greater than that 
in the auxihary reservoir, forces the piston 5 back to the position shown 
in the drawing, recharges the reservoir, and at the same time permits 
the air in the brake-cylmders to escape. To apply the brakes gently, 
a slight reduction is made in the pressure in the main brake-pipe, which 
moves the piston slowly until it is stopped by the graduating spring 9 ; 
at this point the opening /in the slide valve is opposite the port/', and 
allows air from the auxiliary reservoir to feed through a hole in the side 
of the slide valve and through the opening / into the brake-cylinder. 
The passage / is opened and closed by a small valve, 7, which is 
attached to and moves with the piston 5, provision being made for a 
limited motion of these parts without moving the valve 6. When the 
pressure in the auxihary reservoir has been reduced, by expansion into 
the brake-cylinder, until it is the same as the pressure in the main 
brake-pipe, the graduating spring pushes the piston up until the small 
valve, 7, closes the feed opening, /. This causes whatever pressure is 
in the brake-cylinder to be retained, applying the brakes with a force 
proportionate to the reduction of pressure in the brake-pipe. 

To prevent the appHcation of the brakes from a slight reduction of 
pressure, caused by leakage in the brake-pipe, an oval groove is cut in 
the body of the car-cylinder, -^-^ in. in width and -^-^ in. in depth, 
and of such a length that the piston must travel 3 inches before the 
groove is covered by • the packing-leather. A small quantity of air, 
such as results from a leak, passing from the triple valve into the car- 
cylinder, has the effect of moving the piston shghtly forward, but not 
sufficiently to close the groove, which permits the air to flow out past 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^^^^^ 



the piston. If, however, the brakes are 
appHed in the usual manner, the piston 
will be moved forward, notwithstanding 
the slight leak, and will cover the groove. 

When the handle of the four-way cock is turned down, there is a 




Westinghouse Freight Brake Triple Valve. 



direct communication from the main brake-pipe to the brake-cylinder, 
the triple valve and auxiliary reservoir being cut out, and the apparatus 



^""^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



can then be worked as a non-automatic 

brake by admitting the air into the main 

brake-pipe and brake-cylinder to apply 

the brakes. When, from any cause, it is desirable to have the brake 

inoperative on any particular car, the four- way cock is turned to an 

intermediate position, which shuts oiF the brake-cylinder and reservoir, 

leaving the main brake-pipe unobstructed to supply air to the remaining 

cars. 

This position of the handle also releases the brakes on a car when 
it is detached from the locomotive. The engineer's valve used in the 
1886 and 1887 tests is shown by Fig. 52. 

The cut shows the valve in the position for releasing the brakes ; 
the pressure from the main reservoir passing through the rotary valve 
I 3 and to the main brake-pipe, as shown by the arrows. While run- 
ning, the handle of the valve is turned to the position shown in the 
diagram, when the air enters through the feed port, passing the feed 
valve 32, which is held to its seat by the spring 33, which causes an 
excess of pressure in the main^reservoir over that in the brake-pipe equal to 
the strength of the spring 33, and insures a quick release of the brakes. 

The chamber A is connected to a small reservoir, not shown in the 
cut, which simply serves to increase the effective capacity of the cham- 
ber. To apply the brakes, the handle is turned to the position for 
application shown in the diagram, and a portion of the air in the cham- 
ber allowed to escape from the supply port, causing a corresponding 
reduction of pressure in the chamber, after which the handle is turned 
to put the valve on lap. The excess of pressure in the main brake- 
pipe over that in the chamber A forces the piston 1 8 up, unseating the 
valve 22 and allowing air to escape through the exhaust from brake- 
pipe, until the pressure in the brake-pipe is equal to that in the chamber, 
the valve 22 remaining open until the pressure is equalized throughout 
the train, when this valve is returned to its seat by the spring 27. If 
a very considerable reduction of pressure is made in the chamber A, 
the piston 1 8 will move far enough to carry with it the slide valve 2 3 
and allow the air to escape more rapidly by uncovering the two exhaust 
ports. In case of emergency the handle may be turned to the extreme 



Fig. 52 




Westinghouse Engineer's Valve* 



THE 

BURLINGTON 
BRAKE TRIALS 



^""^'"'^ Air Brake Tests 

right, connecting the direct application 
port with a large exhaust port and releas- 
ing the pressure in the brake-pipe with 
great rapidity. 

The Eames Vacuum Brake, 

The Eames vacuum automatic brake, as used during the 1886 tests, 
operated in a reverse way to the Westinghouse. The latter obtains its 
power from air stored at high pressure in a system of pipes and cylinders, 
the former obtained its power from the atmospheric pressure upon the 
exterior of rubber diaphragms, when a vacuum is produced within. 
The following principal parts of the Eames vacuum brake were thus 
described : 

1 . The Ejector, the function of which is to produce a vacuum in the 
diaphragms. 

2. A continuous line of i i^-in. pipe connecting the ejector with the 
diaphragms throughout the entire length of the train. 

3 . The Couplings, which are attached to the end of the flexible hose, 
and form the connection between the different cars. 

4. The Diaphragms, from which the air is exhausted, causing the 
pressure of the atmosphere to force the rubber disk into the iron shell, 
and sets the brakes. 

5 . The Reservoirs, in which a vacuum is maintained, and into which 
the air in the diaphragms is constantly exhausted by a movement of the 
ejector lever, or in case of accidental breakage to the trainpipe or 
couplings. 

6. The Valve, which forms the connection between the automatic 
pipe and the vacuum reservoirs, and between the reservoirs and the 
diaphragms. Its functions are to control the passage of air from the 
brake diaphragms to the reservoir and partially or wholly apply the 
brakes ; or to admit air to the brake diaphragms and partially or wholly 
release the brakes. 

The ejector is shown by Figs. 53 and 54. It has two jets, the 
larger being to produce the required vacuum in the trainpipe and reser- 
voirs, and the smaller to maintain the vacuum against leakage, if any. 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^''^'''^ 



in the apparatus. The larger jet is em- 
ployed only when the immediate creation 
or restoration of the vacuum is necessary, 
in charging the train or releasing the brakes. The smaller jet, having 
a diameter of -^^ of an inch, is used continuously, except when the 
brakes are applied. 

The illustration shows the valves in their usual or running position. 
Steam is admitted at F into the steam chamber surrounding the valve J. 
In this chamber are two ports, C and D, the former admitting steam 
to the larger jet, and the latter admitting steam to the smaller jet. The 
valve J, covering the steam-ports C and D, and the valve H, covering 
the air-port E, are operated by the same valve-stem, which is connected 
with the engineer's brake-lever in the cab. In the running position the 
ports E and C are closed, and D is open. The brake-lever is in the 
notch in the center of the quadrant to which the lever is attached. 

To create a vacuum in the trainpipe and reservoirs (to release the 
brakes or restore the power after the brakes have been applied), the 
brake-lever is moved to the forward notch in the quadrant. This opens 
steam-port C, but does not open port E. Steam passes through port 
C into the chamber surrounding air-tube A, exhausting the air from 
trainpipe G through check valve K, creating a vacuum in the reservoirs 
and trainpipe. At the same time steam is passing through port D into 
the smaller jet B, which is thus aiding the larger jet in creating the 
vacuum. 

To apply the brakes, air is admitted to the trainpipe. The ejector 
lever is moved to the rear notch, closing ports C and D, and opening 
to its full extent port E, through which air is admitted directly to the 
trainpipe, destroying the vacuum therein. To release the brakes, the 
lever is returned to the forward notch ; uncovering both ports C and 
D, and closing port E. 

To partially apply the brakes, the lever is moved to the second 
notch in the rear of the running position. This closes port D, and 
opens the offset shown in the upper left-hand corner of port E. 
This admits a small quantity of air to the trainpipe, slightly reducing 
the vacuum therein, and operating the train valves as hereinafter de- 




Fig. 55.— EAMES BRAKE VALVE. 



^""^'"'^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



scribed. A sufficient amount of air being 
admitted the brake-lever is moved to the 
first notch forward of the running posi- 
tion, closing the offset in port E, but not opening port D, thus main- 
taining in the trainpipe the degree of vacuum resulting from the slight 
admission of air, until more air is admitted for a further application of 
the brakes, or the trainpipe is exhausted to release the brakes. 

The cut. Fig. 55, show^s the valve used in 1887. In the one 
used in 1886, the release valve w^as connected directly with the bell- 
crank and required a greater variation in vacuum to open it. The de- 
scription appHes to both. 

The valve is placed between the diaphragms and the reservoir, 
the reservoir being exhausted through it. Its functions are to control 
the passage of air from the brake diaphragms to the reservoir, and 
partially or wholly apply the brakes ; also to admit air to the brake dia- 
phragms, and partially or wholly release the brakes. This is accom- 
plished by the valves M and L. These valves are moved by the bell- 
crank levers shown in the cut, which are controlled by the flexible dia- 
phragms F and N connected with them by links. 

A vacuum is maintained in the interior of the valve through check- 
valve D, which lifts when air is being exhausted from the trainpipe, 
and closes when air is admitted to it. An equal vacuum is maintained 
in the chamber outside of diaphragm F, which is connected directly 
with the trainpipe by passage E above check valve D. The external 
air is admitted to the outside of diaphragm N through the aperture O. 
Diaphragm F has, therefore, a vacuum on both sides equal to the 
vacuum in the trainpipe. Diaphragm N has the same vacuum on the in- 
side, and atmospheric pressure on the outside. The diaphragms differ in 
size, and the connections with the bell-crank lever are at such angles 
that, as the bell-crank revolves about its fulcrum, the effective leverage 
of N increases, while that of F decreases. As the pressures on the two 
diaphragms are varied, the bell-crank will revolve to a point where the 
diaphragms balance each other, and are in a state of staple equilibrium. 
The valve is operated, therefore, by increasing or decreasing the vacuum 
in the chamber outside of diaphragm F. During the running of the 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^^"^^ 



train, the same vacuum is maintained on 
both sides of diaphragm F, and the dia- 
phragms and bell-crank assume the posi- 
tion shown in the cut. 

In this position the valve L is seated on its upper seat, closing air- 
port K, and opening communication betw^een the interior of the valve, 
through passage G, w^ith the chamber above diaphragm H, thus creating a 
vacuum in this chamber, and lifting diaphragm H from opening P, and 
permitting the air, through ports J, opening P, and pipe B, to pass to 
the brake diaphragms, the air having in this manner free access to the 
brake diaphragms w^hen the brakes are not applied. The valve M is 
closed, shutting oiF communication between the brake diaphragms and 
the reservoir, which is connected with the interior of the valve through 
a pipe entering the valve on the side towards the reader. 

When the brakes are applied, the operation is as follows : Air is 
admitted to trainpipe C. Check- valve D is seated, cutting off com- 
munication between the trainpipe and the interior of the valve. The 
air flows into the chamber outside of diaphragm F through the passage 
E, increasing the pressure upon the diaphragm F, and overcoming the 
resistance of diaphragm N. Diaphragm F moves towards the interior 
of the valve, causing the bell-crank to revolve away from valve L, 
which seats itself on its lower seat, cutting off communication between 
the interior of the valve and the chamber above diaphragm H, through 
passage G, and admitting the external air to chamber H through port 
K. This shuts off the communication between the external air and the 
brake diaphragms through ports J, opening P, and pipe B, by dropping 
diaphragm H and closing opening P. The movement of the other arm 
of the bell-crank lifts valve M, opening communication from the brake 
diaphragms through pipe B with the interior of the valve, and thence 
to the reservoir, collapsing the brake diaphragms and applying the 
brakes. 

If sufficient air is admitted to the trainpipe to destroy the vacuum 
therein, the valve M is opened wide, and the brakes are quickly and 
fully applied. If only a small quantity of air is admitted to the train- 
pipe, the vacuum outside of diaphragm F is only slightly reduced. 




^r^^"!^ 




^""^'"'^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



causing diaphragm F to move a propor- 
tional distance towards the center of the 
valve, revolving the bell-crank away from 
valve L and partially opening valve M. As the air flows from the 
brake diaphragms into the reservoir, the vacuum in the interior of the 
valve is reduced, which causes diaphragm F to move gradually toward its 
normal position, closing valve M, retaining a partial vacuum in the brake 
diaphragms, and producing a partial application of the brakes. Further 
slight admission of air to the trainpipe will, in this manner, cause pro- 
portionally increased applications of the brakes. 

To release the brakes, air is drawn from trainpipe C and the cham- 
ber outside of diaphragm F, and also from, the reservoir and the interior 
of the valve, equalizing the vacuum on both sides of diaphragm F, and 
at the same time restoring the vacuum in the reservoir, which has been 
partially destroyed by the admission of air from the brake diaphragms. 
This causes the diaphragm F to return to its normal position, revolving 
the bell-crank away from valve M (which becomes seated) and raising 
valve L, thus opening the chamber above H to the vacuum in the 
reservoir, w^hich raises H and releases the brakes. 

Fig. 56 shows the Eames driver brake used in the tests. Equal 
pressure is applied to both sides of all the driving wheels, with the 
object of avoiding strain upon either the journal or side-rod bearings. 

The American Brake, 

The American freight-car brake had a centrifugal governor on the 
axle, which at certain speeds, 11 to 12 miles an hour, moved a forked 
lever surrounding the axle horizontally, and this, by a mechanical con- 
nection, threw in or out of gear a push-bar which was immediately back 
of the draw-bar, but out of reach of the draw-bar, thus making the 
brake operative or inoperative, according to the position of this push- 
bar. Except for this disengaging gear, the American brake was exceed- 
ingly simple, consisting of nothing more than a large bent pendant 
lever, the upper arm of which w^as bent against the end of the draw-bar, 
while the lower arm pulled violently on the brake-rod. The push-bar, 
which the centrifugal governor raised and lowered, was merely a hinged 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^''^^ 



extension of the upper arm of this lever. 
The device is show^n by Fig. 57. The 
brake beam, it w^ill be observed, was 
dropped to the floor, in order to better show the brake rigging. This 
brake, as with the others coming under the buffer type, could be operated 
with any form of engine brake. During the trials, the American Brake 
Company used its own steam-engine brake, which was already successfully 
introduced on many railroads. 

The Widdifield & Button Brake, 

The Widdifield & Button was a friction buffer brake, and is shown by 
Fig. .58. It consisted of a small shaft parallel with the axle, one end 
of which was carried in a fixed bearing and the other in a lever actuated 
by the draw-bar on the end of the shaft. Near the movable bearing 
was a large friction pulley, which bore against a combined soft metal and 
paper* spool on the axle ; on the other end of the shaft was the brake 
chain spool, and beyond that again a ratchet which caused the spool. to 
turn with the shaft when the car was moving forward, but not when 
backing. This shaft had therefore to be set to work according to the 
direction in which the train was moving, which could be done from either 
the top or side of the car by a rod connection ; the same motion of 
the handle set the rod and chain which moved up the friction shaft, so 
that they also worked only when going forward. This Company made 
some of its stops with the Westinghouse engine, and others with the 
Fames engine. 

The Rote Brake, 

The Rote buffer brake had a centrifugal governor attached to the 
axle, which, at a certain speed, 4 to 5 miles an hour, allowed the main 
brake-lever to come in contact with the draw-bar. The brake-lever was 
connected with the brake-rod by means of a swiveling-piece pivoted on 
the end of the main brake-lever. As the latter moved, one end of the 
swiveling-piece came in contact with a fixed wiper, causing the other 
end to swing around until it was on a dead center with the pivot at the 
end of the brake-lever, thus taking up a lot of slack without losing 




Fig. 57.— the AMERICAN BRAKE. 




Fig. 58— the WIDDIFIELD & BUTTON BRAKE. 



^""^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



power. In other words, the power in- 
creased as the stroke progressed until it 
reached 6 -in. stroke; after that it remained 
the same up to 8 in. The general features of the brake are shown by 
Fig. 59. The parts, as shown, are somewhat displaced by the body 
of the car being jacked up several inches, removing the bent lever 
under the body of the car from the bearing which it should have 
against the vertical lever, as indicated by the dotted line. The Rote 
Company used the American steam-engine brake and engine during the 
stops. 

Apparatus Used in the Tests. 

The speeds at the stop-posts and during the down-grade runs were 
regulated by means of the Boyer Railway Speed Recorder, of St. 
Louis, one of which was fitted to each engine. 

The device is shown by Fig. 60. By reference to the engraving 
it will be observed that the machine was contained in a compact oblong 
cast-iron case, 6 in. wide, 7 in. long and 8 in. high ; it weighed about 
20 pounds. It was described as follows : 

The machine consists principally of a rotary pump, a cylinder and a 
piston, with mercury as a circulating medium. It is driven at a low 
rate of speed by a coiled wire belt from the truck axle. A port con- 
veys the current from the pump to the lower end of the cylinder, and 
another port, whose area is increased or decreased as the piston rises or 
falls, returns it to the pump. While the machine is at rest the piston is 
retained in its lowest position by a spring, and the return port is then 
nearly closed ; but, when given motion, the pressure causes the 
piston to rise until the port is just large enough for the current to escape, 
thus producing an equilibrium between the tension of the spring and the 
pressure of mercury; or, in other words, the machine simply weighs 
the various pressures of mercury produced by the pump, which is in di- 
rect proportion to the speed of train. 

Attached to the piston-rod, which passes up through the cylinder cover, 
is a pencil placed in contact with a strip of paper. As the paper is moved 
in the direction the locomotive travels, the speed in miles per hour, the 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^""^^ '^' 



distance and the direction of travel, are 
recorded thereon (the height from the 
datum Hne denoting the speed). 

The drum which actuates the paper is driven at a uniform rate of 
speed of ^ in. per mile in the standard machine (those used at brake 
tests moved paper 2 in. per mile). Gripping rolls hold the paper in 
contact v^ith the drum, and are so connected that the operation of a 
lever removes the rolls and pencil from the paper at the same time. 
The paper is wound on two wooden cores and placed with frictional 
contact on upright spindles, which form extensions to the rotary pump- 
shafts and always revolve in one direction. As the locomotive is moved 
forward or backward the paper is transposed from one spool to the other. 

There is also attached to the piston-rod, and carried through a tube, 
a small wire which operates a gauge with a 5^ in. dial. This gauge 
is placed in a convenient position in the engine cab, so that the engineer 
can read at any moment the speed in miles per hour his engine is run- 
ning. 

In the recorders used in 1886, the pump was made to run in which- 
ever way the locomotive moved, and the direction of the current from 
the pump to the cylinder was controlled by valves. The experience 
had at Burlington, as well as in shop tests carried on at the same 
time, demonstrated that this construction could not always be relied 
upon, on account of leakage of valves. In the machines used in the 
1887 tests these valves were discarded and the pump arranged to revolve 
always in one direction, without regard to the direction in which the 
locomotive travels. Otherwise the machine was practically the same 
as that used in 1886. Facsimiles of records made by this machine are 
shown by the speed diagrams in plates VIII. and IX. and Figs. 96 to 
99, pages 226 to 229. 

The Dynamometer Car used during the brake tests was constructed 
by the Chicago, Burlington & Quincy Railroad Company in July, 
1884, from drawings received from the Pennsylvania Railroad Com- 
pany. It was 3 I ft. long, weighing 3 1,650 lbs., and was equipped with 
2 four-wheel trucks fitted with 3 3 -in. wheels. 

The car contained mechanism for recording autographically the train 




Fig. 59.— the Fs.OTE BRAKE. 





Fig. 60.— BOYER SPEED RECORDER. 



^""^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



resistance and speed at all points in the 
run. The resistance was obtained by 
noting the compression of the springs in 
the dynamometer draw-bar. The motion of these springs was com- 
municated by means of levers to a pen marking on the record-paper, 
which passed across the dynamometer table at right angles to the motion 
of the pen. Motion was given to the paper by means of gearing driven 
by a worm on the rear axle of the forward truck. The speed of the 
paper was such that 2 ft. of paper corresponded to one mile of track 
traversed by the car. A stationary pen marked on the paper the datum 
line. This line coincided with that made by the spring pen when no 
force was exerted on the draw-bar. When force was exerted, the 
strain line left the datum, rising above in case of a pull and falhng 
below the datum when a push was exerted on the draw-bar. The 
distance between the strain and datum lines equals twice the amount of 
compression of the springs (see plate II.), ^ in. compression giving 
I in. divergence of the lines, corresponding to about 6,000 lbs. pressure. 
The speed of the car was" obtained by means of a pen attached to 
the armiature of an electro magnet, marking on the paper at intervals of 
5 seconds, being connected in the circuit with a clock which com- 
• pleted the circuit at that interval of time. The distance between the 
successive 5 -second marks measured in 30ths of an inch gives the speed 
in miles per hour. The distance run during the application of the 
brakes, or any point at which an observation was taken, was obtained by 
means of a pen similarly connected with an electro-magnet, marking 
on the paper on the opposite edge to the time-pen upon completing the 
circuit, by means of a push-button. During the tests this pen was 
operated by an observer on the engine, electric connection being fur- 
nished by means of a cable leading back to the car. The observer 
marked on the paper the instant brakes were applied and the moment 
the train was stopped. The distance apart of these points measured 
in inches and multipHed by 220 ( 2 ft. to the mile equals 220 ft. to the 
inch ) gave the run in feet. The pens being in line, the speed and 
train resistance at the instant of application of brakes could be readily 
observed. 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^^^-^^ 



The time between brakes applied and 
stop was obtained by stop watches, the 
signals being the motion of the pen 
operated by the observer on the engine. 

Plate II. is a copy of diagrams of stops as recorded by this 
dynamometer car. These have been selected to illustrate the work of 
the mechanism just described, for a short time previous to and after a 
stop as well as during a stop. They show Stop No. 1722, 50 empty 
car train, Westinghouse electric brake; and No. 1122, 50 mixed car 
train, Westinghouse electric brake. 

The diagrams also show the method of recording the information 
obtained. A curve, represented by dotted lines, showing the retarding 
effect of the brakes, is constructed by erecting at the center of the 
5 -second intervals an ordinate equal to the ^' velocity-head " of the 
train, due to the speed in that interval. The ^^velocity-head" is the 
height of the equivalent grade of retardation, or the grade on which, if 
the train were ascending it without frictional resistance, it would have 
been stopped by the action of gravity alone in the same distance as it 
was actually stopped by the brakes and rolling friction. ( See editorial 
in the Railroad Gazette of May 15, 1885, on the Calculation of the 
Efficiency of Brakes, by A. M. Wellington.) 

The stops shown indicate the effect of the brakes on light and heavy 
trains. In the former case the 50 empty car train, in which the brake 
force approximately equals the train weight, gives a tension diagram 
during the stop showing that the brakes are effective in holding the train ; 
and the engine brakes being also effective and properly adjusted to the 
weight braked, hold the engine in a similar way, so that the position 
of the engine with regard to the train remains the same after the brakes 
are on as before application. The reverse is shown in the diagrams 
of the mixed trains, where the train weight being largely in excess of 
the brake force, causes the cars to run forward on to the engine, com- 
pressing the dynamometer draw-bar as indicated. 

As a check on the dynamometer record, and for service in case of 
accident to the regular mechanism, a second means of obtaining data as 
to distances and speeds was introduced ; this was the American District 



Distance 427 ft. 




1 

1 


sooo 








ft 


p 


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i 




AVestingUouse Brake 

50Eiupty CarTraia 

No. 1722 





6.5' 2i.5 




36 




'. ... J1<L „„- „L. 



Speed iu Miles per 1 

DYNAMOMETER - CAR DIAGRAM 




DYNA3IOMETER - CAR DIAGRAM 



^""^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



Telegraph register, with two independ- 
ent ink-writing pens. In this machine 
the record was printed on a small paper 
tape, which was run by clock-w^ork beneath the recording pens, one of 
which was operated by the observer on the engine, being connected in 
the same circuit as the distance recording pen of the dynamometer 
paper, and marked on the tape the points *' brakes applied" and 
*' stop." The remaining pen was connected with a circular plate 
holding 8 contact points, which, as the plate was revolved by means 
of a belt connection with the front axle of the forward truck, passed 
under a spring jack, completing the circuit for an instant and causing 
the pen to make a mark on the tape. The number of these marks 
or dots included between the points ^'brakes applied" and ^^ stop " 
determines the distance run, the distance from the last contact to full 
stop being noted. The distance between the contact points represented 
15.71 ft. of track and also the speed of the car. 

The dynamometer paper was run throughout the course, the mile 
posts being marked thereon for the purpose of checking the speed of 
the paper ; the register- tape was run only during the stops. 

The dynamometer records alone were used during the 1886 trials, 
but in the 1887 tests both the register and dynamometer figures were 
considered. 

The autographic recording apparatus used in the middle car of each 
train was devised and constructed by the American Brake Company 
especially for these tests. Its records have been invaluable to the Com- 
mittee. The device as used in 1886 is shown by Fig. 61, and was 
thus described at the time : 

The various records taken by this single instrument are as follows : 

1. Beginning at the left-hand side of the diagram, a Boyer speed 
indicator, the invention of Mr. Joseph G. Boyer, of St. Louis, Mo., 
shows the speed in miles per hour on the high dial. 

2. The paper roll just below the high dial is fed horizontally at 
varying rates of speed, at ^-in. per mile for long trips and at about 
100 ft. per inch for records designed to cover stops only. The speed 
is recorded by a diagram on this roll. 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^'"^"'36 



3. On this diagram 5 -second marks are 
made by a pencil actuated by an electric 
circuit from one of the batteries below, 

passing through the clock and the magnet visible near the top of the 

high paper roll. 

4. The low dial near the front of the table gives the distance run to 
the nearest foot after the apparatus is thrown into gear, which is done 
by a handle placed on a shaft seen behind the two battery boxes, and 
which throws everything on the table into gear at once. One of the 
hands on the dial makes a complete circuit in 100 ft.; the other moves 
only one notch for 100 ft., or makes a complete circuit in 10,000 ft. 

5. The rod seen running through the floor connects with the brake- 
rod and actuates directly a pencil, concealed from view by the tall paper 
roll, which records on the latter continuously (it being fed by the same 
mechanism which actuates the distance indicator) the tension on the 
brake-rod, and hence (by multiplying the latter by the proper lever- 
age) the pressure on the brake-beam. 

6. Time-marks at 5 -second intervals are placed on this diagram also 
by the same clock, but by an independent circuit. 

Thus the four elements of speed, time, distance, and brake-beam 
pressure are all given and autographically recorded. 

In the 1887 tests some slight changes were made in the machine ; 
the speed recorder was combined with the stress indicator, both diagrams 
being made on the same paper. The motion was transmitted from the 
axle by a belt made of coiled wire running on adjustable grooved pul- 
leys. The difficulty of slip in the belt connection as used in 1886 was 
thus in a large measure avoided. Accurately turned steel-tired wheels, 
without coning, were also used in 1887 under this car, in place of cast- 
iron wheels as in 1886. 

The accompanying diagram. Fig. 62, shows a typical stop from the 
exceedingly interesting and instructive record obtained from this 
instrument. The figure represents stop No. 811 of 1887, Car- 
penter electro-atmospheric brake, emergency stop, 50 empty car train, 
level track. The record was taken in the 26th car from the engine. 

The perpendicular line at the extreme right indicates the moment the 




Fig. 6i.— the AUTOGRAPHIC RECORDING APPARATUS. 



Fig. 6 2 



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I 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ''''^' '^^ 



engineer received signal to apply brakes. 

The curved line of the upper diagram 

show^s the pressure of the brakes upon the 
v^heels, the horizontal parallel lines indicating the pressure in steps of 
i,ooo lbs. ; the full perpendicular lines give each 25 ft. of the stop, 
v^hile the dotted perpendiculars indicate the time in one-second intervals. 
The curve in the lower diagram shoves the speed, giving the gradual 
decrease at all points until the stop is made. The horizontal parallel 
lines in this case indicate the speed in miles per hour, vs^hile the full 
and dotted perpendiculars have the same signification as in the upper 
diagram. It will be observed from this diagram that with an initial 
speed of 231^ miles an hour, in 7 seconds a 50-car train was stopped 
in 150 ft. 

The Tests. 

The tests were formally opened July 13 th, and continued without 
interruption until August 3d. 

Tabulated Statements, 

The results are shown in the series of tables just given. 

Series B, 1886, plate III., groups the stop tests of the different 
competitors under each competition, ranking them in their order of 
shortness of stop corrected to a uniform speed. The inequalities of 
the brake gear are not taken into computation. Data is given on 
page 149, under the heading of '^Foundation Gear," which will 
enable those desiring to do so to work out the possibilities under other 
conditions of foundation gear. On this table the ''kind of stops" are 
placed in accordance with their importance, viz. : the 2 5 -car trains 
appear first, then the 50-car train, with brakes used on the forward 30 
cars only, and finally the 50-car train, with brakes on all cars, ranking the 
empty train first, then the mixed train, and, lastly, the loaded train. 
It will be observed the representatives of the independent brakes quickly 
dropped out of all tests requiring consecutive braking on more than 30 
cars. The American made one trip over the course, with brakes on 
50 empty cars, but quickly succumbed, leaving the field undisputed to 
the continuous brakes represented by the Eames and the Westinghouse. 














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2, ' 















THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^^-^^ ^^^ 



Series C, 1886, plate IV., has been 
prepared with a view to showing in a 
more condensed table the general results 

of the tests. The following stops have been averaged, correcting 

for the exact speeds, but not for grades : 

25 mixed car trains — all brakes Emergency. 

50 empty do. do. Service. 

50 do. do. do. Emergency. 

50 mixed do. do. Service. 

50 do. do. do. Emergency. 

A notable feature on this table is that the hand brakes used on the 

Chicago, Burlington & Quincy and the Lehigh Valley trains show a 

higher efficiency than the Rote automatic brake. 

Slideometer, 

On each of the previously mentioned tables a column will be observed 
headed^ ^ Movement of Shdeometer, Rear Car, Inches." 

At an early stage of the tests the unlooked-for shocks in the rear car 
made it evident to the Committee that an exceedingly important element 
in a long train contest was not provided with any registering device. 
The want of such a device became all the more apparent with the 50- 
car trains, which, it was estimated, increased the violence of any 
particular shock in a greater ratio than the square of the number of cars 
added. 

Moreover, each individual was more or less influenced in his sense of 
any given shock by his preparation to receive it, in person as well as in 
mind. The sliding movements of some of the tool boxes and loads 
during the earher stops suggested to the referee the impact gauge, or 
** Shdeometer," as it was immediately named. On the 9th morning 
of the test the Shdeometer was first used, and its records at once became 
one of the most important during the contest. 

The device consists of a wooden trough 14 ft. long by 6 in. wide, 
made of clear white pine, smoothly planed. This trough is screwed 
fast to the center of the rear car. In the trough slides in either direction 
a wrought-iron weight 5 in. in diameter and ^ in. high, weighing 16^ 



^"^^^^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



pounds. Crude as the device may ap- 
pear, it has answered its purpose perfectly. 
Shocks in ordinary handling of trains 
with slack couplings over sags, hog backs and working in yards, will 
move the disk from 2 to 8 in. ; i 2 in. has been estimated as sufficient to be 
injurious to live stock and equipment. Repeated blows of i 2 to 20 in. 



To Hand Brake 




Fig. 63 

American Bufier Brake, St. Loais & San Trancisco Cars. 

in the mixed and loaded car tests were sufficient to start the loads at the 
rear of the train through the ends of the cars ; the loaded car thus, through 
the movement of their loads7 becoming a check in weighing the length 
of the shdeometer movement that was admissible and inadmissible. 




Fig. 64 

Total Brake Leverage for [^ ^ruc^l to 8.4^ 
Eames Vacuum Brake, ludianapolis^Decatur & Spxlngfield Cars. 

Foundation Brake Gear, 

In the application of brakes to equipment, one of the most important 
details is the foundation gear or parts that are common to both hand 
brakes and power brakes, and equally essential to the efficient working 
of the one as the other. But very little appreciation of the importance 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^^^^^-^^ 



of this was shown by railroads at that time, 
judging from the fact that thousands of 
freight cars of 40,000 pounds capacity 
and over were running, and being built with the old inefficient foundation 
gear, applied only to one truck. It might have been expected, however. 



To Rear Truck 



To Rear Truck 




Pig. 65 

Eote Buffer Brake, Chicago, Eock Island & Pacific Cars. 

that the competitors in such an important series of tests as these would at 
least have seen that so vital a detail was arranged in such a way that would 
produce a proper equalization of power over the eight wheels of each 
car. Such was not the case. By referring to Figs. 63 to 6^ of the 




Pig, 66 

Total Brake Leverage for one Car, I To 9.2 
■^estinghouse Automajtic Air Brake, Chicago. Burlington & Quincy Cars. 

brake-gear, it will be observed that two only of the ^n^ competitors of 
1886 (Figs. 66 and 6^^ had the braking power properly equalized. 
Fig. 63 is equalized properly for hand brakes, but not for power brakes. 



^''^''^' Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



We give on the next page a table taken 
from the Railroad Gazette of July 30, 
1886, showing the comparative efficiency 
of the five competitors of 1886. 

No attempt has been made to deduct these sources of error from the 
table of stops, though it is clear they should not be allowed to weigh in 
impairing the value of any power brake. 

By reference to the table of stops it will be noted that no hand- brake 
stops were made with the Indianapolis, Decatur & Springfield train. 

To Brake Wheel ,<^ ^ ^ To Rear TrucTi 



^]= 



--^J 



' Fixed 




Fig. 67 

Widdifield & Button Friction Buffer Brake, Lehigli Valley Cars. 

This was owing to the fact that its hand-brake rigging was only con- 
nected to one truck. It would therefore have taken the brakemen 
twice as long to have applied the same number of brakes that they did 
with the trains of the other competitors, which had the brakes of both 
trucks connected. 

Break-i?i-Two Tests — Special No, i, 1886. 

One of the most important features of continuous brakes is the con- 
trol given trainmen of stopping the train at any point in case of emer- 
gency without communication with the engineer, which may be done 
by breaking a hose coupling or by opening stop-cock on the rear car. 



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^""^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



This advantage will be more fully appre- 
ciated by those who have watched the 
frantic endeavors of brakemen on the top 
of a long train to signal a stop to the engineer who has started before all 
was ready in the rear. Similar experience came up every now and then 
during the tests, which at once resulted in the windmill arm motion of the 
brakemen crossways with the track. It was not long, however, before 
they discovered the power that was in their control in handling the West- 
inghouse and the Eames train, and the celerity with which they discarded 
the arm motion and opened the rear stop-cock or parted a hose-coupling 
was remarkable and fully equal to the passenger conductor's confident 
pull on the conductor' s valve of the automatic air brake when he wishes 
to stop a train promptly. Special Test No. i, or the break-in-two 
test, was intended especially to develop this feature of a freight train 
brake and was creditably performed by the Westinghouse and the 
Eames companies. The other competitors obviously from their con- 
struction were unable to participate in this competition : 

Table XIV. on next page" shows the result of the tests. The trains 
were parted between the thirteenth and fourteenth car, counting from 
the engine, the train being composed of 25 cars, mixed loads. In 
test 145 I of the Eames, owing to a misunderstanding of orders, the 
engineer was not allowed to work his ejector after the breakaway oc- 
curred, which resulted in the rear train running into the forward one 
with some force and damaging two of the cars. In the subsequent tests, 
by working the ejector, the brakes were kept off the forward train until 
all danger of colhsion was passed. 

Down-grade Run — General Test No, j. 

One of the severest tests, and the one most dreaded by the compet- 
itors' engineers, was the down-grade run described in the competition 
as No. 3 of the general tests. The train was composed of 50 cars, 
half loaded and half empty cars, and in addition the dynamometer and 
way car. The ground selected for the run was the stretch of track be- 
tween stop No. 3 and the distance post covering 2.021 miles. The 
speed passing stop-post No. 3 was to be 20 miles per hour, and re- 



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^"^''^^ Air Brake Tests 

duced as soon as practicable to i 5 miles, 
which was to be maintained uniformly 
during the remainder of the run. The 



THE 

BURLINGTON 
BRAKE TRIALS 



S 







anoq jad saiira ni paadg 



general result of these runs can be best 
obtained from the speed record diagrams, 
which are shown in reduced scale by Figs. 
68, 69, and 70. 

The horizontal lines show the speed in 
miles per hour, while the vertical lines 
show the time at 5 -second intervals. The 
figures show the time in minutes. Allow- 
ing 30 seconds to reduce the speed to i 5 
miles an hour, the run should have occu- 
pied about 7^ minutes. The diagrams 
showed very plainly great room for 
improvement in both the Eames and the 
Westinghouse brake, and were it not for 
_the low speed would apparently have 
given the award to the American Brake 
Company, for up to 9 minutes it will be 
observed the speed was uniformly main- 
tained between 8 and 10 miles per hour. 
This record, however, it should be borne 
in mind, was taken in the autographic car 
placed in the middle of the train. While 
the persons riding in this car and the dyna- 
mometer car were commenting on the 
uniformity of the run that was being 
made, although somewhat below the 15- 
mile speed, an entirely different record 
was being registered in the rear or 5 2d 
car. Here shock after shock was being 
received, their rapid succession adding to 
their intensity. Twenty-eight blows of 
more or less severity were given during 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^""^^ '^^ 



the run of iij4 niinutes, culminating in 
a shock of 63 in., which broke the train 
in two. An examination of the train 
after the stop revealed the fact that 9 of the rear cars had their ends 
broken and bulged out by the shifting of the loads to such an extent that 
they were in a dangerous condition, and this, notwithstanding the fact 
that the wheels with which the cars were loaded had been stowed with 
special care and the ends of the car blocked with timber. This test 
was more instructive than any other could possibly have been, in show- 
ing the inherent weakness of brakes actuated by independent pulsations 
or blows transmitted through the draft springs. The record is all the 
more prominent as, notwithstanding the shock-producing powers devel- 
oped by the continuous brakes in 50-car train stops, their down-grade 
runs were comparatively free from shocks : — 



Eames test No. 1223- 


-I bump, 2^y'. 














do. No. 1233- 


— bumps. 














Westinghouse test No. 


1243 — Bumps i. 


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do. do. 


1263 — do. I, 


5 
T6"- 












The following are some of the shocks 


during 


the 


American's 


^morable run : 
















1st bump — 17^". 
















9th do. —1 81-". 
















13th do. —2 if". 
















1 8th do. —2 3-1". 
















27th do. — 63". 
















Total number of blows. 


28. 















Dynamometer Car Diagrams, 

We give (Plate V.) a few of the dynamometer-car diagrams of the 
50-car trains, at stop two, which appeared in the Railroad Gazette 
of October 4, 1886. They are thus described : 

Each of the diagrams given consists of two parts : 

I . A direct photographic reproduction of the original record diagram 
taken in the dynamometer car. 



''"«' '^7 Air Brake Tests 

2. A constructed diagram, drawn on 
the original sheets above the original 
machine record from data furnished by 



THE 

BURLINGTON 
BRAKE TRIALS 



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it, to represent the efficiency of the 
brakes during the stop or the rate at 
which the energy of motion was destroyed. 
This also is in effect an original record, 
since it follows it precisely, but it is re- 
constructed in a different and clearer 
form. 

The lines on the diagrams which be- 
long to the first class (original records) 
are these : 

(A.) The base or zero line, drawn 
on the diagram paper, as it is drawn 
slowly forward by the machinery by a 
separate pencil. 

- (^0 The irregular line drawn by 
the pencil connected with the dynamo- 
meter spring, which indicates the tension 
or compression acting in the draw-bar be- 
tween the tender and first car. If the 
line is above the zero base line it indicates 
tension, or that the engine was pulling 
the train ; if below it, compression, or 
that the train was pushing on the engine 
and tender brakes. 

(C.) The time or speed record, 
given by electrically recorded dots at 5 
seconds interval along a separate line, 
which have been transferred for engraving 
to the base line, and will be seen drawn 
upon it. (Some few have been lost in 
engraving. ) 

( D . ) The beginning and end of every 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^^^^^-^^ 



Stop, as electrically signaled from the en- 
gine. This also was recorded on a sep- 
arate line, but for constructing the dia- 
grams was indicated by long vertical lines at the beginning and end of 
each stop, 

(E.) The time of application of the brakes on the middle car was 
accurately recorded by an apparatus on that car, and has been trans- 
ferred to these diagrams by a mark shown thus — M — along the base 
line. The time in seconds from the signal to the rear car that brakes 
had been applied on the engine to the time when the brake was seen 
to go on the rear car was also noted and the record transferred to these 
diagrams marked thus — R, In many of these stops these records were 
imperfect or not taken at all, so that they do not always appear. 
■ (F. ) The distance run is an actual measurement from a row of 
stakes, merely checked ( and some few important errors discovered ) 
by the diagram records. 

(G. ) In the 50-car mixed and loaded tests it will be seen that there 
is a long stretch before the stop proper began (500 ft. in the 20 miles 
per hour stops ; 1,000 ft. in the 40 miles per hour stops) where steam 
was shut off. This was done to reduce as much as possible the severe 
shocks resulting from the application of the brakes by letting the train 
close up somewhat before the brakes were applied. The speed of the 
train fell, of course, after the steam was shut off, but the speed was taken 
at whatever it was in passing the stop-post. 

(H. ) This initial speed is shown in figures, in miles per hour, on 
the vertical line at the beginning of each stop, just above the base line. 

(I.) The movements of the impact gauge in inches are shown by 
small circles at the end of horizontal lines, starting from the first vertical 
as a base. The length of the horizontal line is proportional to the 
movement of the gauge, and the latter is also given in figures. Where 
there was only one shock, there is only one of these lines ; where there 
were several there is a line for each. When there was a shock too 
slight to move the impact gauge the small circle is put directly on the 
base line. 

The impact gauge was not thought of nor invented until the ninth 



^^^" ^-^^ Air Brake Tests 

morning of the tests, after most of the 
2 5 -car tests and some of the 50-car tests 
had been made. Consequently only a 
portion of the diagram show this record. 

The diagrams of the No. 3 and No. 
4 stops, made on the down grade, were 
similar in all essential respects to the No. 
I and No. 2 stops, which have been en- 
graved, except that they were longer be- 
cause of the down grade. The buffer 
brakes make a somewhat poorer relative 
showing on these down-grade stops, as is 
natural from the fact that they depend on 
the force with which the engine crowds 
back against the train, which is reduced 
on down grades, but it does not appear 
necessary to engrave them also, as all = 
necessary details of the action of the i 
brakes are shown in the diagrams en- \ 
graved. S 

Those are the autographic records, 
and before explaining the constructed dia- 
grams, which are the most conspicuous 
feature on the sheet, we may explain some 
features of the dynamometer record. 

The stop begins in all cases at the right 
of the diagram. The engine was then 
always pulling with more or less force ; 
with how much may be read from the 
diagrams by a vertical scale of 23,400 
lbs., or 1 1 . 7 tons, per inch (on the original 
6,000 lbs. per inch). On the signal 
to apply brakes the throttle was instantly 
closed, and we should expect, therefore, 
that the traction would instandy fall to - 



Speed fn miles per hour 




SE 



2 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^^^^^^^ 



zero, but it will be seen that this was 
never the case. By the combined eiFect 
of the steam left between the throttle and 
the piston, the evaporation of any entrained water in the steam chest 
and pipes, the re-evaporation of any condensed steam in the cylinders 
(all this steam, of course, being more or less superheated as the pres- 
sure fell, and expanded as long as there was any left to expand), a very 
considerable amount of work was done by the engine (three different 
ones were used) for several strokes after steam was shut off, with an 
economy of steam, no doubt, which would make any road the envy of 
its neighbors, if it could be habitually realized. It was made entirely 
certain that the throttles did not leak appreciably, yet it will be seen 
that this effect was invariably apparent for from 50 to 200 ft. after 
steam was shut off, despite the action of the driver brakes to coun- 
teract it. 

The engine machinery having been once brought to a state of equi- 
librium, however, it will be apparent that, whatever the absolute 
efficiency of the brakes as a whole, if the engine brakes were retarding 
the engine, and the train brakes retarding the train, at the same rate, 
there would be neither push nor pull on the dynamometer draw-bar, 
but the traction line would fall down to the zero base line and remain 
on it during the stop. In no case did this occur, even approximately. 

If, on the other hand, the engine brakes are acting decidedly more 
efficiently than the train brakes, the engine will push back against the 
train, and the traction line, which in the beginning indicated tension, 
will fall below the zero line, indicating compression. In every one of 
the diagrams this takes place, and in most of them, after an inexplicably 
long interval of 5 to 10 or more seconds, the driver brakes took hold 
with intense vigor, long before the train brakes began to act effectually. 

If, then, later in the stop, the car brakes ^^get a good hold" or the 
driver brakes weaken, or both, the train will pull back on the engine and 
the traction line go back to tension, or above the base line. This occured 
in all the Westinghouse and in many of the Eames stops. 

The buffer brakes, since they derived their power from compression of 
the draw-bars^ necessarily must have had the engine holding back against 



^^^^^^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



the train (in other words, have had the 

car brakes less efficient than the engine 

brakes) or they would not act at all. 

Hence, after the brakes began to act, they all showed considerable and 

continuous compression. 

The average compression or tension during the stop, or various parts 
thereof, was accurately determined by planimeter measurements in the 
usual way, and is recorded in tons (2,000 Ibs.^ of compression (or 
tension) on the diagrams. 

We come now to the constructed efficiency diagram, shown in the 
network of squares just above the traction record, and drawn on the 
same zero line as a base line. 

The precise nature of this diagram we can best explain in this way : 
Turn the sheet upside down. The solid line running across each 
diagram is now the profile of an up-grade which would have brought 
the train to a stop, or down to any given speed, in precisely the same 
distance and in the same time and the same way as the brakes actually 
did. 

If the action of the brakes had been precisely uniform from beginning 
to end of the stop, a grade to imitate its effect should be a straight 
grade, like those shown by the long, straight dotted hne across each 
diagram. If the brakes took hold badly at first, and better and better 
toward the end, as in most cases they did, a grade to imitate their effect 
should be an easy one at first, and grow steeper and steeper toward the 
end, as is the case with most of them. If the action of the brakes was 
irregular, taking hold and then letting go somewhat, the ' ^ grade ' ' 
should also be irregular, as it is in some of them. 

If we wish to determine what length the stop would have to be, had 
the brakes been as efficient throughout as they were during the latter 
end of the stop, we have only to prolong the final ^^ grade" down (or 
up) to the point A, where we strike the level at which our ^^ grade" 
starts. This has been done on every one of these diagrams, and the 
rates in per cent, (i per cent. =5 2. 8 ft. per mile) are shown, first for 
an average grade, which would have stopped the train in the same dis- 
tancC;, but not in just the same way as the brakes did, and, secondly, of 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^^ '^' 



the grade corresponding to the efficiency 
of the brakes towards the end of the stop. 
These percentages also show the retard- 
ing effect of the brakes in lbs. per loo lbs. o^ total weight of train. 
The more satisfactory basis of comparison, however, is in lbs. per i oo 
lbs. of load on braked wheels, which will appear in the tabular 
records. 

The vertical lines of the diagram show distances of loo ft., starting 
from the beginning of the stop, and hence leaving a fractional distance 
at the end. The horizontal lines are for speeds of 5, 10, 15, 20, and 
25 miles per hour. They are not spaced equally, however, but ac- 
cording to the energy represented by that velocity. A train moving at 
20 miles per hour has four times as much stored energy or momentum 
to be destroyed by the brakes as one moving at 10 miles per hour, and 
that again as one moving at 5 miles per hour. Consequently, the 
5 -mile line is very close to the zero base line, and the others are at 
increasing intervals apart. 

The diagram was constructed thus : The dynam.ometer paper being 
moved at 2 ft. per mile, and check-marks being electrically recorded on 
it at 5 -second intervals, a scale of 30 parts per inch reads off the speed 
in miles per hour during that 5 seconds. When the speed is decreas- 
ing during a stop these marks come closer and closer together on the 
paper. The space between each was read, a perpendicular erected in 
the middle of each space, and the energy corresponding to that speed 
in vertical feet of potential lift laid off by a uniform arbitrary scale. 
The efficiency line was then passed through these points without correc- 
tion. In a few cases where corrections seemed needed they have been 
indicated by a dotted line, but the full line is the actual uncorrected 
record. 

Some irregularities of the diagram are due to the effect of slack. 
There being several feet of slack in the train, and the record being that 
of the front car, a sudden increase of driver-brake efficiency could check 
back the front cars and cause a great apparent retardation, which would 
be lost in the next 5 seconds by the whole train crowding upon it when 
the slack came all out. 



^"-^^^^-^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



General Tests, 

At the beginning of the trials your 
Committee viewed, with some dismay, 
from the number of competitors with trains, the long series of tests 
each expected to go through and the prolonged work that would 
necessarily follow. At an early day, however, it became evident that 
few, if any, of those who had participated in the joint meetings at 
which the tests were framed, realized the perfection the brake problem 
must attain before any competitor could successfully go through a pro- 
gramme such as had been mapped out. The result was a gradual 
dropping out of the weaker contestants, as they were called upon to 
perform the more severe competitions. These failures materially short- 
ened the contest. 

The Rote Brake Company, in some preliminary work before the 
trials commenced, developed such complete lack of braking power that 
an extension of time was asked in which to remodel the mechanism. 
This was readily granted. On the 17th and i8th days, towards the 
end of the contest, one run each was made over the course with a 25 
mixed car train, emergency stops. The complete failure of the brake 
in making any record is shown in tables series B and C of 1886, plates 
III. and IV., stop numbers 1751 to 1754, ^^^ ^^3^ ^^ ^^34- ^^^ 
Widdifield & Button friction buffer brake early in the contest developed 
an entirely unlooked for feature, in making its quick stop record, which, 
perhaps, surprised no one more than it did the inventor of the brake. 
In making stops with 2 5 -car trains, and brakes on all cars, a succession 
of violent shocks was produced in the rear. The brakes were very sen- 
sitive, and the very fact of the retardation due to their going on also 
served to pull them oiF; the released cars, as soon as they exhausted 
their slack, buffed against the engine, which action at once reapplied 
the brakes, to be almost as quickly released again, and so on in alternate 
succession until the final stop was made. A readjustment of the brake 
was asked for and allowed, which decreased the number of shocks in the 
rear, but at a sacrifice in the length of stop. The succession of shocks, 
however, though in a diminished form, was still so apparent that it was 
not considered prudent to attempt any stop with brakes on 50 cars, and 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^""^''^^ 



the Widdifield & Button stops were in 
consequence confined to runs with trains 
having automatic brakes on 25 and 30 
cars only. Unfortunately there is no sHdeometer record of these earher 
tests ; the necessity for such a device did not force itself on those in 
charge of the contest until the ninth day. 

The American Brake Company entered the trials in a very unpre- 
pared condition, and consequently under decided disadvantages. A few 
weeks prior to the contest their equipment, which had just been built 
and was ready for preparatory work, was completely destroyed by a 
fire at the shops of the builders. A new lot of cars was at once 
ordered, but not completed until after the contest had commenced. 
The American Company, therefore, was obliged to enter with practi- 
cally an unproved train. They, nevertheless, pluckily took their place 
in the contest, and after some adjustment succeeded in making a fair 
record in the trains with 25 cars braked, as will be seen by the figures 
in plate III. They then entered the 50 empty car train, all cars 
braked, making one service and one emergency run over the course. 
Here it was clear the limit was reached. The additional cars de- 
velop the violent successive shocks of the Widdifield & Button train to 
such an extent that it was not deemed safe to make any stops with 
the 50 mixed or loaded trains, all cars braked. The down-grade run, 
however, with the 50 mixed car train was tried, which, while unfort- 
unate for the brake company, shed a flood of light on the action of 
independent brakes that will be invaluable to railroad companies for 
years to come. 

Thus towards the close of the contest the only surviving competitors 
were the Eames and the Westinghouse, and even with these, such 
violent shocks were given in stops with all 50 cars braked that the 
Committee was obliged to amend its rules, and convert the 50 mixed 
and loaded car stops into service stops ; that is to say, stops that an 
engineer would make in the ordinary handling of his train with a view 
to avoid any damage in the rear, rather than to make his shortest 
possible stop. It will be noted, therefore, in plate III., that in these 
stops the engineers were allowed to shut off steam 500 feet and 1,000 



^""^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



feet before reaching the stop-post, and 
thus bunch the train before the stop signal 
was given, and even then gradual applica- 
tion w^as made in place of emergency. Had these precautions not 
been taken, a continuance of the shocks not only would have been 
exceedingly dangerous to those riding on the train but would soon have 
rendered all cars unfit for service. The explanation of the violence of 
the shock with the continuous brakes clearly is the same as in the inde- 
pendent brakes, viz., successive application from the engine. The 
intervals in 25 and shorter car trains had not been sufficient to fiilly 
bring this out. It was only when the jump was made to a 50-car train, 
together with the natural desire of each competitor for a record of the 
shortest stop, that successive apphcation assumed the shape of impracti- 
cability. This readily accounts for the 50-car trains, with only auto- 
matic brakes on the forward 29^ cars, in the shorter stops so closely 
equaling (in some cases surpassing) the emergency stops with brakes on 
the 50 cars. 

^Table XV. 

















0,0 ^: 












t3 -6 




0^5 












u u 

















2 5 


iSs 


w 0^ 




Kind of stop. 


Name. 




c 




0^ c 












£ ^ 


^•1-^ 


bX) (U M 













«« -0 














Z 


^% 


r 


^S's 


50-car train, 


engine 


; and 29^ car brakes 


Westinghouse 


1,631 


SI 


1,380,102 


313 


do. 


do. 


and all car brakes . 


do. 


621 


52 


1,404,190 


307 


do. 


do. 


do. 


do. 


611 


^2- 


1,404,190 


340 


do. 


do. 


and 29 j/^ car brakes Eames . . . 


1,821 


S2 


1,246,050 


34S 


do. 


do. 


and all car brakes . 


do. . . . 


521 


SI 


1,383,897 


348 


do. 


do. 


do. 


do. . . . 


511 


51 


1,383,897 


383 


do. 


do. 


and 29 ^ car brakes' American . 


1,321 


so 


1,521,094 


396 


do. 


do. 


and all car brakes . do. 


831 


52 


1,576,260 


392 



At stops 2, 3, and 4, where longer time was occupied in the stops, 
more brakes went on, and consequently shortened the stops to some 
extent. Perhaps a still better appreciation of this slowness of applica- 
tion may be had from an examination of the brake-beam stress diagrams. 
It will be observed from the reading of the diagram that in Westing- 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests "^^^^^^^ 



house stop No. i6i i. Fig. 98, page 228, 
a close-coupled 50 empty car train, speed 
22 miles, distance 418 feet (corrected to 
20 miles, 345 feet), no force whateyer was exerted against the wheels 
of the 25 th car until nearly 13 seconds out of a total of 18 had elapsed 
and 364 feet of the stop had been made. In a corresponding Eames 
stop. No. 521, Fig. 96, page 226, speed 22.4 miles, distance 437 feet 
(corrected to 20 miles, 348 feet), the first application is compara- 
tively much better, viz. : 8 seconds out of a total of 19, and, at a 
travel of 250 feet, this great advantage, unfortunately for the Eames 
ompany, is completely lost by the exceedingly slow development of 
power, which is well brought out by these middle-car diagrams. A 
glance down plates VIII. and IX. at the 1887 diagrams will show 
how fully the competitors realized the imperfections in their 1886 
mechanism. 

Slack and Close Coupled Train. 

As pertaining to the question of shock in successive application of 
brakes, it was apparent the amount of slack in each train would have 
considerable influence in increasing the violence of any shock. The 
Committee determined to ascertain to what extent this influence might be 
reduced, by ehminating as much of the loose slack as was practicable. 
We quote the test as reported in the Railroad Gazette of August 6, 
1886. 

^^The Westinghouse train of Burlington & Quincy cars, from which 
the severest shocks have been received and which likewise had the most 
slack, was selected for the test. For the test a lot of 3 in. scrap arch- 
bars were cut up into pieces about 12 in. long, punched and riveted 
together near the centers, making a very snug fit in the hnks. No 
trouble was experienced from their jumping out, and they took out 3 in. 
of 31^ full slack. The result was certainly very decisive and convinc- 
ing. 

*'The train was made up of 49 empty cars, or within one of the 
same number as had been used in the earlier empty cars emergency runs. 
While the stops were on an average quite as good as the previous 



^""^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 







Speed. 


Stop No. 


1611 . 


. . 22 


do. 


1612 . 


• • 39K 


do. 


1613 . 


. . 26 


do. 


1614 . 


• • 43 



Time. 


Impact Gauge. 


18 seconds. 


iSy'g^ inches. 


23K do. 


ISH do. 


ijyi do. 


19^ do. 


25 do. 


21^ do. 



emergency stops, the shocks were of 
the following mild and gentle de- 
scription : 

**Test No. 1600, Westinghouse, 49 empty car train, emergency stops, 
close couplings — 

Distance. 
418 feet. 
959 do. 
513 do. 
1,106 do. 

'^ A 20-inch bump will throw a car-load of stock toward one end 
of the car in very energetic fashion, but is a very different affair from a 
i20-in. bump, at which figure the Westinghouse loose-coupling shocks 
were estimated. 

^^The amount of slack in the Chicago, Burlington & Quincy cars 

may be estimated for each train about as follows : 

Loose 
slack. 

In link . . . . . 3 ^ in. 

From bending of pins and occasional slack springs in draw- 
bars ^ in. 

In springs, 2^^ in., total motion in 15,000-lb. springs, all of 
which (and considerably more, if there were more) is, 
beyond question, used up in every shock, but wnth a 
diminution of the force of the blow% so that the 4^ 
in. of spring slack may be estimated as the equivalent 
in free slack of 2 ^ in. 



Total free slack or equivalent 6^ 

Of which there was taken up by the blocks 3 



Leaving in close coupled train, per car . . . 3 i^ in. 
Or nearly as may be half as much free slack, with the result that, 
with a 50 empty car train : 
6y2 in. of free slack, 27 ft. in the train, give an impact at 

the rear of (estimated) 120 in. 

31^ in. of free slack, 14^ ft. in the train, give an impact 

in the rear of 20 in." 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ""^^^'^^ 

A more convincing demonstration that 
slack added to the intensity of shocks in 
trains making stops or in passing over hog- 
backs and dips of undulating road-beds could hardly be made. 

■ Conclusions, 

The results of these 1886 tests w^ere disappointing. None of the 
competitors did satisfactory w^ork, owning to the violent shocks produced 
in stopping. Slack in long trains controlled w^ith power brakes, applied 
successively from the engine, assumed at once a most prominent part in 
this and doubtless all future contests. The expected delays in charging 
and releasing continuous brakes w^as show^n to be of no moment, and 
while the objections of successive application was developed to an extent 
calling for the most serious consideration, there clearly was a future for 
continuous brakes in more instantaneous application which their inde- 
pendent competitors could never hope for. Few now will be found 
spending their energies on the Buffer type of brake. No clearer evidence 
of its impracticability can be given than the fact that successive appli- 
cation is one of its indispensable features, and the gradual withdrawal of 
this type of brake from the attention of the railroads in this country 
dated from the Master Car Builders' contest of 1886. 

Abandonment of Endurance Test, 

The Committee's work as laid out had in contemplation an endur- 
ance test of nine months' regular service. The contest, however, had 
developed so many points where improvements might be made, that at 
a meeting held in New York in the month of September, following the 
1886 contest, it was decided to abandon the endurance test and its 
restrictions. 



GENERAL TESTS, MAY, 1887. 

(i.) 50 empty car train over the course prescribed, making four 
emergency stops : 

No. I stop, on level, 20 miles per hour. 

No. 2 stop, on level, 40 miles per hour. 

No. 3 stop, 53 ft. grade, 20 miles per hour. 

No. 4 stop, 53 ft. grade, 40 miles per hour. 

(2.) 50 mixed car train, ^ of the cars to be loaded to their full 
capacity, and ys to be empty; 75 per cent, of the latter to be in the 
front half of the train ; four emergency stops : 

No. I stop, on level, 20 miles per hour. 

No. 2 stop, on level, 30 miles per hour. 

No. 3 stop, 53 ft. grade, 20 miles per hour. 

No. 4 stop, 53 ft. grade, 30 miles per hour. 

(3.) 50 mixed car train, with hand brakes and engine, and tender 
automatic brakes ; four emergency stops : 

No. I stop, on level, 20 miles per hour. 

No. 2 stop, on level, 30 miles per hour. 

No. 3 stop, 53 ft. grade, 20 miles per hour. 

No. 4 stop, 53 ft. grade, 30 miles per hour. 

(4.) The 50 mixed car train to be let down a grade of 53 feet per 
mile, 3 miles long. Speed of 20 miles per hour at the top of the grade, 
to be reduced to i 5 miles per hour as soon as practicable, and main- 
tained without material variation all the way down the grade. 

(5.) 50 mixed car train once over the course. Brake shoes to 
have a slack of from ^ inch to 3/^ inch each ; four emergency 
stops : 

No. I, on level, 20 miles per hour. 

No. 2, on level, 30 miles per hours. 

No. 3, 53 ft. grade, 20 miles per hour. 

No. 4, 53 ft. grade, 30 miles per hour. 

(6.) 50 empty car train, engines brakes only to be used; i stop, 
on level, 20 miles per hour. 

(7.) Engine tests; engine and dynamometer car; 2 stops on level 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^^^^^^^ 



track at 20 and 40 miles per hour, and 
2 stops on 53 ft. grade at 20 and 40 
miles per hour. 

(8.) 50 empty car train, hand brake stop, with engine and tender 
automatic brakes ; once over the course prescribed, making 4 emergen- 
cy stops : 

No. I stop, on level, 20 miles per hour. 
No. 2 stop, on level, 40 miles per hour. 
No. 3 stop, 53 ft. grade, 20 miles per hour. 
No. 4 stop, 53 ft. grade, 40 miles per hour. 

Special Tests, 

(9.) 50 mixed car train ; tests to be made on level. Trains to be 
broken in two or more unequal parts. After trains are broken any as- 
sistance necessary shall be rendered by the brakeman, who will be rid- 
ing on the rear of the train or on the engine when the breakaway occurs : 

No. I breakaway, on level, 20 miles per hour. 

No. 2 breakaway, on level, 30 miles per hour. 

(10.) 50 empty car train; train resistance test : 

No. I. To pass No. i stop-post at 20 miles per hour, letting the 
train drift till it stops, no brakes being appHed. 

No. 2. To pass No. 3 stop-post at 5 miles per hour, letting the 
train drift until No. 4 post is reached, at which point the accelerated 
speed shall be recorded and the train stopped. 

The same arrangement of dynamometer-car and middle-car record- 
ing apparatus to be used as in the first trials. 

May, 1887, Brake Tests, 

The May, 1887, tests were made over the same course as in 1886, 
and with practically the same recording apparatus and detailed rules, 
with a few modifications suggested by the tests of last year. The 
Committee were again indebted to the following corps of assistants, and 
the railroad companies they represented, for valuable aid during the 
contest : 

Assistants on Engine — R. W. Bailey, Assistant Engineer of Tests, 



^^^^^^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



P., C. & St. L. R'y Co. ; S. P. Bush, 
Mechanical Engineer's office. P., C. & 
St. L. R'y Co.; W. C. Squire, Test 
Department, C, B. & Q. R. R. Co. 

Assistants in Dynamometer Car — F. W. Sargent, Engineer of 
Tests, C, B. & Q. R. R. Co. ; W. W. Nichols, Assistant Engineer 
of Tests, C. B. & Q. R. R. Co. ; E. P. Lord, Penn. R. R. Co. 

Assistants in Middle Car — Wm. Forsyth, Mechanical Engineer, C, 

B. & Q. R. R. Co.; H. Guels, Mechanical Engineer, American Brake 
Co.; W. H. Peirce, Mechanical Engineer' s office, C, B. &Q. R. R. Co. 

Assistants in Way Car — R. Ryan, Mechanical Engineer's office, 

C, B. & Q. R. R. Co. ; E. W. Penfield, Test Department, C, B. 
& Q. R. R. Co. ; A. H. Bowman, Electrician, Lehigh Valley R. R. 
Co. ; W. Nettleton, Superintendent of Brakes, Kansas City, Fort 
Scott & Gulf R. R. Co. 

At the May, 1887, tests ^v^ companies were represented. 

The Westinghouse Air Brake, Pittsburg, Pennsylvania. 

The Eames Vacuum, Boston, Massachusetts. 

The Hanscom Air Brake, San Francisco, California. 

The Carpenter Automatic Electro Air Brake, i 5 Gold Street, New 
York, N. Y. 

The Card Electric Brake, Cincinnati, Ohio. 

It will be observed that only the continuous type of brake entered 
this year's contest. The 1886 tests had shown clearly that quick 
application on long trains was the only method of avoiding the shock at 
the rear of the train. Special attention had been given this by the 
competitors ; even the Westinghouse and the Eames companies coming 
in 1887 with electric appliances adapted to their brakes, through which 
they could obtain instantaneous application. It is a well-recognized 
fact that there is no mechanical difficulty in getting any amount of brak- 
ing power on a car ; the difficulty has been in getting a quick applica- 
tion. 

Westinghouse Brake, 

The Westinghouse Company used 50 Pennsylvania Railroad standard 
60,000-lb. cars, the average weight being 30,577 lbs., and fitted with 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^^^^ '^' 



the Janney coupler. The brakes were 
fitted this year with the quick-action triple 
valve. The first sharp reduction of air 
put the triple valve nearest the engine into action, and the air it drew from 
the trainpipe started the next triple, and so on throughout the entire train. 
Figs. 71, 72, and 73 represent sections and plan of this triple 
valve; Fig. 72 is a different section of the lower part of Fig. 71. In 
working the ordinary triple valve of the Westinghouse automatic air 
brake, air passed in through the trainpipe by the openings a, b, c. 
Fig. 71, into the drain- cup A, from whence it went up through holes r. 
Fig. 72, into the chamber B, Fig. 71, pushed up the piston 5 and the 
shde valve 6 connected with the piston. This was the normal position 
of the apparatus when the train was running. The piston and slide 
valve attached being up, the brake-cylinder was open to the atmos- 
phere by means of the passages and ports d, e, f, /, q. To apply the 
brake, air was permitted to escape from the trainpipe, which reduced the 
pressure at B, when the higher pressure in the auxihary reservoir pushed 
down the piston 5, carrying with it the slide valve 6, thereby putting 
the auxiliary reservoir, by means of the port /, open to the brake cylin- 
der. The degree of opening, and hence the quickness of application, 
was in direct proportion to the reduction of pressure made in the 
trainpipe. 

The new triple valve worked precisely the same way as the old one 
when a light reduction of air was made in the trainpipe. But when a 
quick stop was wanted sufficient air was exhausted at first to make piston 
5 push down valve i 5 far enough to open the port s. Fig. 72, when the 
air from the trainpipe rushed up through a suitable passage x. Figs. 72 
and 73, into the brake-cylinder. When the air in the brake-cylinder 
and in the trainpipe came to have the same pressure, the valve 1 6 closed 
automatically, and prevented the air from the auxihary reservoir from 
passing into the trainpipe. At the instant the descent of the piston 5 
moved the valve i 5 and opened the port s for the air in the trainpipe to 
pass into the brake-cylinder, the port m on the slide valve 6, put the 
auxiliary reservoir in communication with the brake-cylinder also. 
When the engineer made the reduction of pressure necessary to start 



^^^^ '^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



the operation which let the air from the 
trainpipe pass into the brake-cyhnder, he 
immediately put the handle of his valve 
on lap, to prevent the passage of air from the main reservoir into the 
trainpipe. By the new arrangements the greater portion of the air in 
the trainpipe was utilized to operate the brake, by flowing into the 
brake-cylinder, instead of being exhausted into the atmosphere. The 
first sharp reduction of air put the triple valve nearest the engine into 
action, and the air it drew from the trainpipe started the next triple, and 
so on it went throughout a train of 50 cars or more. Apphcation to 
the whole train of 50 cars was made in about 6 seconds, compared 
with 17 seconds required with the common triple. 

The electrical device used is explained in the sub-committee's report. 
It consisted of a valve which, by the passage of an electric current, let 
the air in the trainpipe escape into the atmosphere. It was not 
intended to use this valve on every car, but in some three or four points 
on a long train. Its practical effect was, instead of allowing the air to 
escape from the trainpipe only at the engineer's valve, it escaped at 
four points on the train. 

Eames Vacuum Brake, 

The Eames Vacuum Brake Company had 50 cars of 40,000 lbs. 
capacity built to the Chicago, Burlington & Quincy standard for the 
brake company in Chicago. They had also undergone important 
changes during the past year, which have greatly increased the brake's 
efficiency. The diaphragms and auxiliary reservoirs had been enlarged. 
The main improvements, however, were in the ejector, the valve, its 
electric attachment, and the leverage. The leverage was arranged with a 
floating fulcrum, the effect of which was to increase the power with the 
travel of the diaphragm. The brake shoes being hung from the car 
body, their distance from the wheels, and consequently the stroke of the 
diaphragm, was increased when the car was loaded, and the effect of the 
floating fulcrum was to increase the leverage when the car was loaded. 

The description of the Eames automatic brakes as used in 1886 ap- 
plies to that used in 1887, with the following improvements : 

1st. An electrical attachment. Fig. 74, which would apply, release 



Fig. 73 




Fig. 71 

"Westinghouse Quick-Action Triple Valve, 




Fig. 74.— EAMES ELECTRIC BRAKE VALVE. 



^"^^^^-^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



or graduate the application of the brakes 
on all the cars simultaneously. 

zd. A floating fulcrum lever for varying 
the pressure on the brake shoes. Fig. 75. 

It has been explained that the valve w^as operated by the admission of 
air to, or the exhaustion of air from, the chamber outside of diaphragm 




Sames Floating Fulcrum liCver. 



F. This admission and exhaust w^as made through the ejector and train- 
pipe. As the flow of air requires an appreciable time, it follows that 
the brakes on long trains cannot be applied instantly and simultaneously. 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^fEIIl 



If air can be admitted to the chamber outside 
diaphragm F in all the valves in a train of 
any length, at the same instant and w^ith- 
out any loss of time, it follow^s that the brakes would be immediately and 
uniformly applied. To accomplish this w^as the purpose of the electric 
device show^n w^ith the valve in Fig. 74. This consists of a shell, v^hich 
is fastened to the main valve w^ith bolts, and contains two chambers, R and 
F'. Chamber F' is connected with the space outside of diaphragm F by 
the passage F^^ E. This passage is always open ; consequently chamber 
F' is virtually a part of the space outside of diaphragm F. Chamber F' is 
also connected with the trainpipe by passage W, which is controlled by 
the valve V. Y is an electro-magnet actuating the armature Z, which 
moves the valve-stem S T. The valve S controls the admission of the 
external air to the chamber R through port X ; the valve T controls 
communication between chambers R and F'. 

The operation of this electric attachment was as follows : When the 
electro-magnet Y is magnetized, it raises armature Z, which opens the 
valve T, and closes the valves S and V. This allows the air which 
was contained in the chamber R to pass through chamber F' to the 
chamber outside of diaphragm F, actuating the valve as already de- 
scribed. The capacity of chamber R is such that one measure of air 
will apply the brakes lightly — the brakes remaining on as long as the 
circuit is kept closed. The circuit being broken, valve T closes, and 
valves S and V open, allowing chamber R to fill with air through port 
X. A repetition of the movement puts another measure of air into 
the space outside of diaphragm F, and applies the brakes with propor- 
tionally increased force. Breaking the circuit opens valve V, and re- 
leases the brakes. 

As valve V closes the chamber outside of diaphragm F from the train- 
pipe, the vacuum in the reservoirs may be increased by the ejector while 
the brakes are on. To prevent the exhaustion of the air from the 
center of the shell increasing the relative vacuum upon the inside of 
diaphragm F and affecting the application of the brakes, air is also 
exhausted from chamber F', and consequently from the chamber outside 
of diaphragm F, through passage I. In this passage is placed the gravity 



^^^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



valve U, which keeps the vacuum in 

chamber F i in. below^ the vacuum in 

the reservoir. The same vacuum on both 

sides of diaphragm F w^ould release the brakes as before explained. A 

is a check valve to prevent the external air from entering the shell when 

port X is open. 

By this device the engineer could apply and release the brakes instantly 
and uniformly, either in whole or part, throughout a train of any 
length. The current was used only when the brakes were applied, and 
the operation of the valve was not affected if the electric apparatus got 
out of order. 

Fig. 75 shows the floating fulcrum lever, an arrangement for auto- 
matically adapting the braking power to the weight of the car and load. 
The diaphragm washer was connected directly with the brake-lev- 
ers, and the leverage adjusted to give braking power equal to such per- 
centage of the weight of car as was desirable. This power would 
be the same, however, whether the car was light or loaded. A certain 
percentage of the weight of the empty car cannot be exceeded without 
skidding the wheels, when the car is empty, while a very much greater 
power may be applied to the loaded car without skidding. This device 
furnished for empty cars the proper amount of braking power, and in- 
creased it proportionally as the car was loaded. 

The brake being hung from the body of the car, the slack of the 
shoes is greater when the car is loaded, because the shoes are hung be- 
low the center of the wheels, and retreats from the wheels as the load 
compresses the springs. The device shown in the cut could be adjust- 
ed to increase the pressure on the shoes 50 to 100 per cent, by this 
variation in the slack. 

The lever A B was suspended from the links C and D, which are at- 
tached to a rigid support, at F and J. The diaphragm, placed in any 
convenient position, was connected to the lever at H ; the brake-rod was 
connected to the lever at K. When the diaphragm was collapsed by ex- 
hausting the air from its interior, it drew the lever toward it, the point 
H traveling over the path H H. At the same time the point X traveled 
over the path K K'. The numbers show the corresponding position 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^^^^^ 



of the points H and K at different parts 
of the stroke. During the early part of 
the stroke, the fulcrum of the lever was at 
I, while the link D was merely a guide. In the latter part of the stroke, 
the fulcrum was at G' and the link C was merely a guide. At inter- 
mediate points the fulcrum was at some point between I and G'. Hence, 
in taking up the slack the brake-rod moved much faster than the dia- 
phragm, and but little force was expanded ; while, when the blocks 
reached the wheels, the stress had increased very much. The spaces 
between the numbers in the path K — K' indicate the variation in force, 
which is inversely as the distance traveled. When the cars were empty 
the brakes got home at about the point marked 3 . When the cars were 
loaded the brakes got home at about 6, at which point the stress on the 
brake-rod was about double the stress on the empty car. The cars used 
in the test weighed 24,000 lbs. empty. Assuming that 70 per cent, of 
the weight on the wheels was the greatest pressure that could be used 
without skidding the wheels, 16,800 lbs. would be the limit of pressure 
that could have been used on the empty car. When loaded, the springs 
were compressed half an inch. This caused a variation in the slack of i^ 
in. The brake-levers were 5 to i , and the travel of the pull-rod i o to 
I ; therefore a variation of y^ in. in the slack made a variation of 2 i^ 
in. in the distance the pull-rod traveled to bring the blocks home. The 
variation of 2 ^ in. in the travel of the pull-rod brought the lever to a 
position where the stress would be about double, or 33,600 lbs. on a 
loaded car. This result was obtained by inserting the floating fulcrum 
lever in the pull-rod. The proportion of the parts could be arranged to 
suit any desired variation, or to take up the slack with a slight expenditure 
of force and then maintain a uniform pull to the end of the stroke. 

Carpenter Brake. 

The Carpenter automatic electro air brake was fitted to an Illinois 
Central engine and 50-car train, each of 40,000 lbs. capacity, and 
averaging 27,351 lbs. light weight. It consisted of an air pump, main 
reservoir, etc., on the engine, and a brake-cylinder and auxiliary reser- 
voir underneath each car. The trainpipe was always in direct communi- 



^^^^^^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



cation with the auxihary reservoirs. The 

brake could be appHed by letting air out of 

the trainpipe, but it could not be released 

by sending -air into the trainpipe. The brake could also be applied or 

graduated by an electric current which 

operated an electric valve on each cylin- 

11 ,0 1 1 y^ ^^^ ^^^' Another electric valve was used 

to release the brake. 

Fig. 76 shows the general arrange- 
ment for an engine and tender. An 
air-pump placed in any convenient posi- 
tion on the engine compressed the air 
into the main reservoir ; from thence it 
passed through the engineer' s brake-valve 
to the tender, and from there on to the 
rest of the train in the usual way. The 
detail of the brake apparatus used on the 
tender was the same as that used for the 
cars. The detail of the driving-wheel 
brake apparatus, being so similar to that 
in common use, needs no further de- 
scription. The automatic valve for oper- 
ating the same was placed for conve- 
nience under the engineer' s cab. A small 
secondary battery, containing from six 
to eight cells having one ground con- 
nection and one connection to the engi- 
neer's brake valve, conveniently located 
on the engine, furnished the electro- 
motive force for working the valves 
throughout the train. The handle of 
the engineer's brake valves having a 
detachable connection with the plug or 
slide valve thereof, could be turned to 
make the electrical connection between 




THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^^^^^^^ 



the battery and the train wire without 
moving the mechanism used to operate the 
brakes by air ; or the air brake mechanism 
could be operated without making the electrical connections. The 
wires extending throughout the train could be laid either within or with- 
out the air-pipe, but in either case they 
were contained within the air-hose, and 
the simple act of uniting the latter also 
completed the electrical connections 
between the cars. 

Figs. ^^ , 78, and 79 show in detail 
the arrangement of the brake-cylinder, 
auxiliary reservoir, and automatic valve. 
This valvular apparatus contained two 
distinct main valves, as shown in separate 
sectional views. Figs. 80 and 81. The 
first shows section through the brake 
valve '^^." This valve was used in 
applying the brakes, and could be oper- 
ated either by means of an electric current 
or by reducing the pressure in the main 
air-pipe ; in either case air was admitted 
from the auxiliary reservoir into the brake 
cylinder applying the brakes. The other 
view shows section through the release 
valve ^' <^," which could be operated by 
an electrical current only to release the 
brakes. In each case an electro magnet, 
being energized by it, attracted an arm- 
ature and therewith a small tappet 
valve ; this exhausted the chamber above 
the diaphragm, whereupon the pressure 
beneath the diaphragm raised the latter, 
and therewith the brake valve '*/7" or 
the release valve **^" applying or 







^^^^^^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



releasing the brake according as the handle 
of the engineer' s valve was throwm forward 
or backward. To make this valve action 
clearer we give the following more detailed description : Referring to 
the engraving (Fig. 80) of section through brake valve '^i^/' the air 
passed from the main pipe to the plug shown by dotted circular lines, 
thence in between the diaphragm and piston. This pressed the piston 
down ; at the same time the air passed through the piston and into the 
reservoir. At the same time it passed through a small leak hole into 
the chamber above the diaphragm. The whole box was then charged 
with air. When the armature was energized by the electricity passing 
into the magnet, it Hfted a small tapped valve, which blew off the cham- 
ber ; the air pressure below then raised the diaphragm and the whole 
brake mechanism, and 
opened connection to 
the cylinder. When 
the valve was dropped 
by shutting off the 
electricity, the cham- 
ber above the dia- 
phragm was charged 
again and the valve 
closed, closing con- Fig, 78 

nection between the valve and cylinder, and the brake was applied. Refer- 
ring to the engraving (Fig. 8 i ) of section through release valve '^/^," 
in charging the brake-cylinder, the valve chamber in ^^^" was also 
charged. To release the brakes, the electricity over the release wire 
energized the magnet in ^'^," which lifted the armature and opened a 
tapped valve, thus opening connection between the cylinder and the 
atmosphere, which, of course, threw the brakes oiF. 

The valve shown on Fig. 80, while applying and releasing by elec- 
tricity, was capable only of applying the brakes by variation of the pres- 
sure in the main air-pipe. The brake could not be released by raising 
the pressure in the main air-pipe. 

Fig. 82 shows the hose connections, which, while differing from 




THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^""^^ '^' 



the Westinghouse coupling, possessed the 
important advantage of being perfectly 
interchangeable with it, so that cars 
equipped with the two different brakes could be coupled together, and as 
the valves were capable of being operated either by air or electrically, it 
was evident that the two brakes could interchange without difficulty. It 
will be seen that in this coupling the electrical connections were entirely 
within the hose, that the circuit was completed by simply joining the air 




couplings, and that a hose could be readily replaced, no separate joints 
having to be made for the electrical wires. 

Hanscom Brake. 

The Hanscom brake consisted of an air-pump for compressing air ; an 
engineer's brake valve for the distribution of air, two lines of trainpipes 
and a brake-cylinder under each car, on which was an automatic valve 
for setting the brake automatically in case the train breaks in two. The 
brake-cyhnders were made longer than the stroke of the piston, so that 
sufficient air remained in one end to apply the brakes in case of a train 
breaking in two. 



J 



^""^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 




Section through 
Brake valve "a" 



The engineer's brake valve P (see 

Fig. 83) was so constructed that w^hen it 

was in its mid position, which it occupied 

when the train was running, the air from the pump flowed freely through 

it into both trainpipes and into both ends of the brake-cylinder, so that 

the pressure on both sides of the 
. piston was equal. By moving this 

valve either to the right or left, the 
air could be released from either 
end of the brake -cylinder, while 
the opposite end was in direct 
communication with the air-pump, 
and the pressure on that side of the 
piston could be increased to the 
extent of the boiler pressure and 
proportions of the steam and air 
cylinders of the pump. The auto- 
_ matic valve F was attached to the 

rear end of the brake-cylmder, and allowed the air to flow freely 

into the brake-cylinder, but its outflow was retarded by the small valve, 

which was kept to its seat by a 

spring. This spring was adjusted 

to any pressure which it was de- 
sired to retain in this end of the 

cylinder, so that in the event of an 

accident and the train breaking in 

two, a sufficient pressure was 

maintained in this end of the 

cylinder to set the brakes and 

stop the train. The trainpipe 

E had no valve between it and 

the brake-cylinder, so that the air 

had free ingress and egress. N 

is the air-pump ; D and E trainpipes ; other parts show their functions 

clearly. 




THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^'^' '^"^ 



Card Brake. 
The Card was purely an electric brake, 
applied to 50 Cincinnati, Hamilton & 
Dayton cars of 50,000 lbs. capacity, and averaging 26,000 lbs. 
light weight. It is fully described in the subcommittee's report. 
The passage of an electric current caused two drums under each car to 
grip one another. One drum was constantly revolving, being driven 
by a chain from the axle, and the brake-chain was attached to the other 
drum, consequently, when the latter drum was made to revolve, it wound 
up the brake-chain and applied the brake. This brake required some 
special arrangement on the last car of the train, an obvious objection 




Fig. 85J 



Carpenter Brake Hose Couplings. 

during the introduction of the brake on any road, and in this respect 
differed from the other brakes. 

Report of Electric Jpplia?ices, 

The following is the report of the subcommittee appointed to report 
on the various electric apphances, and composed of — 

Mr. A. H. Bowman, Electrician, Lehigh Valley Railroad. 



Tig. 83 




Card Brake. 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^^^^^ 



Mr. E. M. Herr, Acting Superin- 
tendent Telegraph, Chicago, Burhngton 
& Quincy Railroad. 
Mr. O. E. Stewart, formerly Superintendent Telegraph, Chicago, 
Burlington & Quincy Railroad, now Superintendent of the East Iowa 
Division of the Chicago, Burlington & Quincy Railroad. 

Burlington, Iowa, May 25, 1887. 

Mr. Godfrey W. Rhodes, Chairman M, C, B, Brake Committee : 

In pursuance with the Committee's instructions in letter of May 19, 
we have made an investigation of the electrical appliances used by the 
Eames, Carpenter, Westinghouse, and Card brake companies in the 
1887 brake test, and respectfully submit the following report : 

As to the use made of electricity we find the brakes represented 
naturally divide themselves into two classes, one in which electricity 
is entirely depended upon for the proper operation of the braking 
mechanism, the order in which it is used as an auxiliary or addition to 
a braking device complete in itself 

In the first class are found the Carpenter Electro Air Brake and the 
Card Electric Brake. 

In the second, the Westinghouse Automatic Air Brake and the Eames 
Automatic Vacuum Brake. 

All the above are arranged on the open circuit system, with the ex- 
ception of the Card, in which the circuit is closed, but the two batter- 
ies, one on the engine and one in the rear car, are so opposed to each 
other that in the normal condition no current passes through the train. 
In the open circuit system it is to be understood that unless the brakes 
are either being applied or released no current is passing or being 
supplied by the batteries or other electro-generating devices. This is 
also practically true in the closed circuit system employed by the Card 
Brake Co. 

Taking up in order the four brakes examined, we have, first, the 
Carpenter Electro Air Brake. The electrical appliances used by this 
brake company consist of a secondary ^'Julien'' battery of eight cells, 
carried in a box upon the left-hand side of the engine securely fastened 



^"^^"^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



to the frame and guide yoke, and two sys- 
tems of electro-magnets connected in mul- 
tiple arc upon the three-wire system, one 
set of magnets operating the admission, the other the release valves. They 
also exhibited a magneto machine, by means of which the brakes could be 
operated by the engineer independently of the battery. This machine 
was not properly adjusted for the work to be done on these tests, and w^as 
therefore not used. The brake and release valves referred to above are 
shown in section on drawing No. 892 of the Carpenter catalogue 
(Figs. 80 and 81 herewith), in which a full description of the brake 
mechanism is given. Fig. 84 illustrates the manner in which the elec- 
tric apparatus mentioned above is connected in this brake system. 

In this diagram, B^ represents the battery ; H the handle of the 
engineer's valve, which closes the circuit A-X by being moved into 
contact wdth point A or B Z, by being moved into contact with point 
B. In the first case, the current would be caused to flow through the 
magnets M, M^, M^, etc., returning by the common return wire C-Y 
operating the admission valves and applying the brake. In the second 
case, the flow would be through magnets Mj,M2,M3, etc., returning 
over the same wire C-Y, and operating in like manner the release valves. 
The connections between the wires on different cars are made automati- 
cally in coupling the brake hose by means of contact pieces in the hose 
coupling, as shown in Fig. 82. These pieces are held in firm contact 
by a powerful spring, and are well rubbed, in coupling, making a clean, 
firm contact. The wires are run under the bottom of the cars and 
through the hose to the couplings. 

The resistance of each electro-magnate was found to be 200 ohms, 
making for a 50-car train when connected as shown a total resistance 
of 4 ohms. It is worthy of note that, with a battery of constant 
electro-motive force, the resistance being increased inversely as the 
number of cars in the train, a constant current strength is maintained 
through each magnet regardless of the number of cars, making no 
adjustment necessary for different lengths of train. 

With this arrangement of battery and resistance, considerable current 
is used while the circuit is closed, but as this only takes place while the 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^e iss 

pressure is either being increased or de- 
creased in the brake-cyhnder, it amounts 
to but a small consumption of battery, 
even for a number of stops. Calculations show that with a 50-car 
train the braking force could be increased or decreased continuously for 
about 1 7 hours before the strength of the battery would be destroyed, 
and a proportionately longer period for a shorter train. From the way 
in which the circuit is run it is easily seen that, should an accident 
happen to any of the wires, causing their rupture at any point, the 



B 


A 

c 
















1 


1 1 1 1 

^J/I gj/H 9j/III gj/iv ?jfV 


rl-l'I'I'l 


'|l|l|'H^I-J 




C 
( 


> i 


>. ; 


■'" ' 


1 

1 


5 J/6 



Fig. 84 
Carpenter's Electric Apparatus. 




Fig. 85 
Card's Electric Apparatus. 

brakes between such point and the engine would be unaffected thereby, 
while those on the other section would, of course, be inoperative. This 
feature would enable the brakes on the forward section to be released by 
the engineer in case of an accidental break in two. 

We found the conducting wires used fairly well insulated throughout 
their length except at points where connection was made between wires 
to valves and the main conductors. No attempt at insulating of these 
joints is made. Perfect insulation is of great importance in this sys- 
tem, for, should a cross occur between the two conductors, instead 
of the brakes being apphed when an attempt was made to do so, the 



J 



^"^^^^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



release, as well as the admission valves, 
would be open, and should the current be 
maintained, the auxiliary reservoir, train- 
pipe, and main reservoir would all be completely bled. Should either wire 
come in contact with any metallic connection, either with the trainpipe 
or any of the braking apparatus, or any part of the car, forming metallic 
connection with the track, the result would be that either the admission 
valves would cease to operate by electricity and the brakes could not be 
set thereby, or, being set, they could not be released, depending upon 
which wire was touched or grounded. 

Rain, sleet, or snow would work very much to the disadvantage of 
the electric appliances of this brake if the conducting wires are not well 
and completely insulated. It is, perhaps, fair to say that this brake can 
be applied by allowing air to escape from the engineer's valve in case 
the current fails, but cannot be released except by electricity. 

In regards to details, we found the electric appliances admirably de- 
signed and well worked out, giving, in our opinion, under ordinary cir- 
cumstances, a good and reliable arrangement. The magnets and arm- 
atures are inclosed in the cast-iron cap on top of the valve, but are not 
within the compressed air chamber. They are separated from the rest 
of the valve by a heavy brass plate serving to protect the armatures 
from the magnetic influences of the other iron parts of the valve. 

The amount of current used on a 50-car train is about 3 amperes, 
with an electric motive force of 16 volts, the resistance of the circuit 
being about 5^ or 6 ohms. Fusible safety plugs are inserted in the 
circuit next the battery to prevent the possiblity of the magnets being 
burned. 

The next in order is the Card Electric Brake. 

This company uses two secondary batteries of a form devised by the 
inventor, Mr. Card, consisting of i 5 cells each, one situated under the 
engineer's seat on the engine, the other on the rear car of the train, so 
connected as to oppose each other in such a way that no current passes 
under normal conditions. Also a system of three electro-magnets for 
each brake connected in multiple series together with an automatic 
rheostat current indicator and arrangement for cutting in and out as 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^''^^ 



many cells as is desired to give the re- 
quired braking force, all as shown in the 
diagram. Fig. 85, page 188. 

B and B^ are the batteries, M, M^, M^, etc., the systems of elec- 
tro-magnets, one for each brake, connected as shown ; R and R^ the 
automatic rheostats, arranged in such a way that, should the train part 
at any point, the couplings for the wires being so arranged as to close 
the circuit on each section, thus cutting off part of the resistance before 
in circuit, an equal resistance would be automatically inserted at the 
rheostat. This maintains the current at a constant strength, no matter 
how many or how few cars are broken off. The brake is applied while 
running, by either the conductor or engineer moving the handle H or 
H 1 , and thus cutting in or out some of the cells, destroying the balance 
and causing the current to flow through the magnets M, M^, etc., the 
amount of flow, and consequent severity of application of the brakes, 
being regulated by the number of sections over which the handle H or 
H 1 is moved. The resistance of each magnet is low, being one ohm, 
making the resistance of the three used in each car I3 ohm, when 
connected as shown. The total resistance of each car, including con- 
ducting wires, is ^ ohm, or a total of 25 ohms for a 50-car train. 

Although considerable current is required for the full application of 
the brakes, only part of it is necessary for a partial application. The 
current is passing in this system while the brakes are in operation, for 
not only must the current pass to apply the brakes but it must be main- 
tained to keep them on. 

Calculation shows that, with the battery used of a capacity of 10 am- 
pere hours, I o hours of the maximum application of the brake could 
be obtained before the battery is exhausted, and, of course, a propor- 
tionately longer period for gentler applications. 

The conducting wires used by this brake company are not insulated, 
excepting where they are fastened to the body of the car, and consist 
of galvanized iron wire cables, y^ in. thick. The couplings are ar- 
ranged to complete the circuit through one wire by a sHding contact 
piece in the center, the return current passing through the outside casing 
of the couplings. They are designed to pull apart at the couplings under 



^^^''^' Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



all circumstance, for, should the hose and 
contained wires be ruptured, the brakes on 
neither section could be applied. 

The effect of a cross between the conducting wires here would be to 
apply the brakes throughout the train, and, as no effort has been made 
to insulate the conducting wires, this is an accident which, in our opin- 
ion, is extremely hkely to happen either from the direct contact, or by 
rain, snow, sleet, or other causes. The automatic rheostat is also a del- 
icate piece of mechanism liable to get out of order, with the possible re- 
sult of burning out some of the magnets, rendering the brake inopera- 
tive. The principle on which this brake is gotten up is admirable, but 
the mechanism employed somewhat complicated for train service. 

In the second division, we have, first, the Westinghouse Automatic 
Air Brake. 

The electric device used by this company consists essentially of a 
valve inserted in the trainpipe, operated by means of compressed air, 
which raises a piston normally in equilibrium when its balance is de- 
stroyed, by blowing off a chamber above it, by means of a small valve 
raised from its seat by the armature of an electro magnet. The current 
which energizes this magnet is produced by 6 Le Clanche cells, situated 
in the box under the engineer's seat. The current is passed through 
a copper wire insulated with rubber insulation, and run through the 
trainpipe, the return being through the metal of the pipe itself. The 
wire is connected automatically in coupling the air-hose, by means of 
contact pieces in the center of the coupling, giving a firm contact with 
a slight rubbing between the surfaces. The magnets used are wound 
to a resistance of 2 ohms each, and but three being used in these tests, 
the total resistance, about 3 i^ ohms for the magnets, and about 2 ohms 
for conducting wire, is 5 ^ ohms. The battery used would suffice for 
a long time, as the wires are so connected to the engineer's valve that 
no electricity would be used, except for emergency stops. 

The wires are carefully insulated, and, being inclosed in the train- 
pipe, are well protected from the effects of the weather. Should a 
metallic contact occur between the wire and the pipe, however, the re- 
sult would simply be to render inoperative the electric valves which, as 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^"'^^ 



before stated, are entirely auxiliary to the 
brake mechanism. The electric features 
of this brake are well worked out, and, 
in our opinion, give a reliable and practical apparatus. 

The electric appliances to the Eames Automatic Vacuum Brake are 
also auxiliary to the vacuum mechanism itself. It consists essentially of 
an electro-magnet inclosed in a cast-iron cap or chamber, which can be 
put in communication either with the vacuum of the main valve and 
auxiliary reservoir or with the atmosphere, according as the circuit is 
made or broken, as explained on page 24 of the Eames catalogue. 
Also a metalhc circuit composed of a single conducting wire and the 
magnets connected as shown in heavy black lines, plate V, the return 
being through the rails of the track. 

The current is supplied by a small dynamo having an armature 9 in. 
long and 3 in. in diameter ; this dynamo has no governor, and is en- 
tirely beyond control, and varies greatly in speed. The magnets, as is 
seen, are connected in series, making the total resistance equal to the 
sum of the resistances of the conducting wire and all the magnets, ne- 
cessitating a very low resistance in the latter ^ ohm each, and a cur- 
rent of considerable strength to overcome the entire resistance, which is 
for a 50-car train about 30 ohms. 

The conducting wire is fairly well insulated, and, being run through 
the trainpipe, is well protected, except where it is connected to the 
spiral wire through the hose. The effect of any metallic contact be- 
tween the conducting wire and the parts of the car in metallic connec- 
tion with the track would be, as far as the electrical attachment is con- 
cerned, to cut out all brakes between this point of such contact and the 
rear of the train. If the conducting wire be broken or detached, in 
any way causing a break in the circuit, the entire electric apparatus fails. 

No effort was made to protect the armatures from the effect of close 
proximity of iron in the other parts of the valve, and in several ways 
the details of the electric attachments might be improved. The use of 
the track as a return is to be deprecated on account of interruption to 
the current in case of insulated track sections put in block signal systems, 
drawbridges, etc. 



i 



^""^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



It seems to us the whole question of the 
application of electricity to railroad braking 
resolves itselfinto three important questions: 

First, can a valve mechanism be made operative by electricity which 
shall be permanent and practicable for railroad service, not having parts 
too sensitive or of too fine adjustment ? We think it can. The valve 
construction as shown by Mr. Carpenter, the same which he used in 
these trials, is certainly not more delicate and complicated than that of 
the well-known Westinghouse triple valve. 

Secondly, can the electrical conductors for working these valves be 
so insulated and protected as to avoid short circuits and other injuries ? 
We think they can by running the wires inside of the air-pipes where 
they are as little liable to derangement and injury, and become as 
permanent and certain in their flmctions as any other feature of the 
brake mechanisms. In all the electric brakes shown the wires are laid 
inside the air-hose couplings, where they are fully protected, and their 
connections are made from car to car easily and certainly, so that this 
important point is so far settled^^s to require no further explanation. 

The remaining point is the source of electro-motive force. 

Of the different means employed by the companies represented, the 
secondary battery appears the most reliable, giving a constant current 
at all times until discharged, recharging being a simple process which 
can be so methodically and practically arranged as not to interfere with 
the brake service nor add materially to the expense. 

If brakes worked by electricity are to come into general use, it is 
probable that both battery and dynamo will give way to the magneto 
generator, being a small machine, about 1 8 in. square, having an easily- 
turned crank which instantly develops the electro-motive force required, 
so that a turn of the crank will actually apply or release the brake. 
One of these machines was shown us in operation upon an engine and 
tender brake. This apparatus may solve a most important point con- 
nected with the application of electricity to railroad brakes, inasmuch 
as it renders the apparatus on the locomotive independent o{ any special 
stations or round-houses, or any stated period when a battery, if used, 
would have to be recharged. 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^""^''^^ 



We believe, from what we have seen 
at the Burlington Brake Tests and from 
a close personal examination of the several 
electrical arrangements for braking, that electricity properly devised 
and managed may be made a valuable auxiliary to actuate power brakes 
on long trains, and their efficiency considerably increased thereby. 

A. H. Bowman, 
E. M. Herr, 
O. E. Stewart, 

Subcommittee, 
Record of 1887 Tests. 

The trials were opened May 9th, and continued without interrup- 
tion until May 28th or 29th. The Committee were singularly for- 
tunate in being able to go through a prolonged series of tests for a second 
time without any interference from rain or wind which could be claimed 
as having an influence on the stops. 

The Resista?ice of Trains, 

The following figures give briefly the results of the No. 7 special 
tests made to determine the frictional resistances of the various trains. 
The trains were composed of 49 or 50 empty cars with dynamometer 
and way car, and American type engine and tender. The track and 
rails were in good condition and the wind light. 

Each train was tried once on a slightly descending tangent, and once 
on a curve, situated on an average descending grade of 506 ft. per mile. 
The resistance was ascertained on the tangent by running up to stop- 
post No. I, at about 20 miles per hour, and then shutting ofl^ steam 
and allowing the train to run until it came to a standstill. 

The resistance on the combined grade and curve was ascertained by - 
running the train up to stop-post No. 3 at a low speed (about 5 miles I 
per hour), and then shutting off steam and allowing the train to run 
until stop-post No. 4 was reached ; the speeds at the moments of pass- 
ing each stop-post were carefully noted. 

It will thus be seen that the resistances given below include not only 
the resistance of the cars, but of the engine running without steam. 



^""^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



This is probably greater per ton than that 
of the cars, but the weight of the engine 
(about 40 tons) is so insignificant in 
comparison with that of the cars (700 to 800 tons) that the influence 
of the engine in running without steam may be neglected, and the resist- 
ances given may probably be taken to represent fairly the resistance of 
new empty cars. 

1887. 

Table XVI. 





Brake. 


Tangent. 


Curve. 


Pattern of 
Cars. 


Speed. 




Speed. 


J3 






< 


Si 


III 

1 '^ 


Pennsylvania 
111. Cent. . . . 
G.,B. &Q. . . 
St. Jo. & St. L. 


Westinghouse 
Carpenter . . . 
Eames .... 
Hanscom . . . 


15 


15 
15 


5.87 

6.22 

7-51 
12.00 


19 

I5X 

4 


23X 
22X 

20 
4 


8.72 
9.09 

II. 
19.8 


Average . 


n% 


15 


7.90 


I6X 


22 


9.60 







In making this average, the Hanscom results on the curve are 
excluded as they are not based on sufficient data to be trustworthy. The 
^^ mean speed " is the average of the squares of the speeds. 

The cars were new, and were tried empty. The Pennsylvania cars 
were lubricated with dope. The Eames cars when loaded, after these 
trials, gave trouble from hot boxes. The great resistance of the Hanscom 
train was caused by the brake shoes binding on the wheels. The brake 
shoes on the Eames train were also in some cases very close to the 
wheels and apparently affected the friction of the train on the curve. 
The brake shoes on the Westinghouse train were hung inside, all the 
i others were hung outside the wheels. 

The trials on the curve were made between stop-posts Nos. 3 and 
4. About half the total distance is on a 2 deg. 40 min. curve (2,149 
ft. radius), extending over nearly a quarter of a circle (80° 40' 10^^), 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^""^''^^ 



and the remainder of the distance is on 
curves averaging about i deg. or, say, 
about 6,000 ft. radius. 
The results given in similar trials of brake trains over the same ground 

in 1886, were as follow^s ; the trains w^ere, how^ever, composed of 25 

cars, I 2 loaded to their full capacity and i 3 empty. 

1886. 
Table XVTI. 





Brake. 


Tangent. 


Curve. 


Pattern of Car. 


Average 
speed, 
miles. 


Resistance, 
lbs. per ton 
of 2,000 lbs. 


Average 
speed, 
miles. 


Resistance, 
lbs. per ton 
of 2,000 lbs. 


C.,B.&Q. . . . 
1. D. & S. . . . 

Lehigh Valley . . 

St. Louis & San 
Francisco . . . 


Westinghouse 
Eames . . . 
\ Widdifield ) 
\ & Button . \ 

American . . 


20 1^ 


4.32 
6.84 

6.84 
8.50 


26X 

2l34f 

aiX 


6.07 
9.42 

9.42 
8.94 


Average, 1886 

Average, 1887 


16X 


6.62 
7.90 


22^ 
16X 


8.46 
9.60 


Average of both years 


14^ 


7.26 


i9>^ 


9.03 



The Committee are indebted to Mr. A. M. Wellington for the 
calculations giving the results of the trials in 1886. 

The results for the two years agree fairly w^ell. The average differ- 
ence betw^een the resistances on the tangent and on the curve was , 
1.84 lbs. in 1886, and 1.70 lbs. in 1887. One train of cars (West- 
inghouse, 1886) gave a resistance of only 4.32 lbs. on the tangent, 
while another train (Hanscom, 1887) had a resistance of 12.00 lbs. 
per ton on the tangent, or nearly three times that of the C, B. & Q. 
cars in the lighter running train. This difference was apparently prin- 
cipally due to the brake-shoes rubbing against the wheels, and was equal 
to a constant grade against the train of 20 ft. per mile. In running 
from New York to Chicago, 1,000 miles, the extra resistance would 
be thus equivalent to surmounting an elevation of 20,000 ft., or more 



ii 



^"^^^^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



than the height of the highest mountain 
in North America. The importance 
of keeping the brake-shoes clear of the 
wheels is thus very evident. 

In the 1886 trials, the Chicago, Burlington & Quincy, the Indian- 
apolis, Decatur & Springfield, and the Lehigh Valley trains were com- 
posed of cars that had been running some time. The St. Louis & San 
Francisco cars were new. The C, B. & Q. cars (Westinghouse), 
and the Lehigh Valley cars, had the brakes hung from the trucks and 
inside the wheels. All the other cars had the brake shoes hung outside 
from the body. 

The following figures, h)ased on the average results obtained in 1886 
and 1887, show the increased friction on the curve, as compared with 
the tangent. 

Increase, 
lbs. per ton. 

Shoes hung from the truck and inside the wheels . . . 2.30 
Shoes hung from the body and outside the wheels . . . 2.84 

These results tend to show that the resistance on curves is increased 
considerably when the shoes are hung outside and too close to the 
wheels. When the truck swivels, the shoes, being hung fi-om the 
body, are lifted and brought closer to the wheels by the greater inclina- 
tion of the hangers. When the shoes are hung from the trucks, no such 
action occurs, and the shoes remain the same distance from the wheels, 
whether the car is running on a tangent or on a curve. 

The fact that outside-hung shoes rub more forcibly against the wheels 
on curves is not only shown by the figures given above, but was also 
observed when the trial trains were being hauled over frogs and curves 
in the yard at West Burlington. 

The size of journal bearing has doubtless an important influence on 
the friction of trains, and the subjoined figures give the sizes of the 
journals in three of the trains tried at the 1887 tests, together with the 
weight of each car, empty, and loaded to its fiill marked capacity, and 
the resultant load per square inch on the journals. The bearing area 
of the journal is assumed as the length and diameter multiplied together. 

As the frictional resistance given was obtained with empty cars, where 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests "'"^^ "^^ 



the load per square inch on the journal is 
practically identical, the variation found in 
the resistance is due to other causes than 
insufficient bearing surface. The highest amount of friction was shown in 
1887 by the Chicago, Burlington & Quincy cars, which in 1886 showed 
the least. In both years the cars were of the same design, but in 1887 
the cars were new, w^hereas in 1886 they had run over 10,000 miles ; 
the difference was, therefore, probably due to less accurate fitting and 
workmanship as compared with the Pennsylvania and the Illinois Cen- 
tral cars, which were also new, but showed respectively 1.64 and 1.29 
lbs. per ton less friction than the Chicago, Burlington & Quincy cars. 
These differences, insignificant as they may appear, would in running 
1,000 miles necessitate an extra amount of haulage power equivalent to 
surmounting summits 4,330 and 3,415 ft. high respectively, or greater 
than that of any line between the Mississippi and the Atlantic. The 
importance of good fitting is further shown by the Chicago, Burlington 
& Quincy cars running hot when loaded after the resistance test. 

Table XVIII. 



Cars 


Journal, length 
and diameter. 


Weight of Car. 


Pressure per 

Square Inch on 

Journal. 


Friction 
Tangent. 




Empty. 


Loaded. 


Empty. 


Loaded. 




Pennsylvania . . 
111. Cent. . . . 
C.,B.&2- • • 


Inches. 
8X4 
7X4 

7X3X 


Lbs. 
30,577 
27,351 
25,509 


Lbs. 
90,577 
67,351 
65,509 


Lbs. 
119 
122 
121 


Lbs. 

354 
301 
312 


Lbs. 
5.87 
6.22 

7-51 



The Pennsylvania and Illinois Central cars were built at the company's 
shops, and the Chicago, Burlington & Quincy cars were built by a 
contractor. On the other hand, the Chicago, Burlington & Quincy 
cars, in 1887, were all fitted with new lead-lined journal bearings, which, 
practice rather courts less care in first fitting, while the Pennsylvania 
had a hard-metal brass and the Illinois Central a babbitt-lined brass. 
It is not improbable this difference in journal bearings influenced the 
frictional resistance of each train. 



^""^''^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



From these experiments, the following 
figures, probably, represent the frictional 
resistance of long trains of freight cars in 
good repair running over a track in good condition, the weather being 
fine and warm and the wind light. The resistance appears to be con- 
stant at speed of from 12 to 2 5 miles per hour, and does not appreciably 
increase with an increase of speed within these limits. 

Table XIX. — Frictional Resistance, Lbs. per Ton of 2,000 Lbs. 
Speeds 12 to 25 Miles per Hour. 



On Tangent 
On 3° Curve , 




Lbs. 
6.00 
8.30 



Good lubrication and carefully fitted boxes and journals may, with 
cars that have been running some time, decrease this resistance to a 
minimum of 4 lbs. per ton on the tangent, while brake shoes rubbing 
against the wheels and other unfavorable conditions may increase the 
friction on the tangent to 12 lbs. per ton, and to considerably more on 
curves. The use of outside-hung shoes seems to increase the resistance 
on curves when the shoes are very near the wheels. 

Foundation Brake Gear, 
A marked improvement in the foundation gear of the competition of 
1887 over 1886 will be observed by reference to the accompanying 

Westingliouse 

These levers were used in all stops 

prior to No. 1541 

Total T)rake leverage 1 to 9 




figures. The Westinghouse Company used cylinder levers of 9 ^ x 1 8 j^ 
in. prior to stop No. 1541, Fig. 86. In subsequent tests thev used 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^^^^^^^ 



a cylinder leverage as shown by Fig. 87, 

viz. : iQi^ X 17^ in. 

The ratio w^hich the pressure upon the 
piston bore to the pressure on the brake shoes w^as in the first case nearly 
as I to 9, and in the second nearly as i to 10. 

Westinglionse 

These levers were used in stops 
after No. .1541 
Total iDrake leverage 1 to 10 




The same ratio for the Carpenter brake. Fig. 88, w^as i to lo-l, 
and for the Hanscom brake. Fig. 89, i to 14. i. With the Eames 
brake. Fig, 90, this ratio varied on account of the floating lever. 

Fig. 88 Carpenter. 

Total iDrake leverage 1 to 10 Vs 




The Card foundation brake is shown by Fig. 91. 
The braking pressure on one car, it will be observed, was only 86.4 
per cent, of what it would have been if dead levers had been used. 

Fig. 89 Hanscom. 

Total brake leverage 1 to uXo 




which would have brought an equal pressure on all wheels. Therefore, 
there was a loss of efficiency of 13.6 per cent. 

With the then prevailing general indifference to brake gear on 



^^^^^^^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



4-wheel trucks it is not to be wondered 
that the more difficult application to 
6 -wheel trucks was hardly attempted. 

The loss of efficiency by neglecting to brake the middle wheels of the 
6-wheel trucks under passenger equipment theoretically is 33^ per 
cent. This figure was proved by a practical test with a 6 -wheeled 
truck car on the Chicago, Burlington & Quincy Railroad, fitted with the 
brake connections so arranged that the change from brakes on 4 wheels 




to brakes on 6 wheels could be easily effected. On many prominent 
roads the most important trains are equipped almost exclusively with 
6-wheel trucks. The needless loss of braking powder under these cars 
has, since the inauguration ot these tests, become thoroughly realized 
and generally remedied. 




Card, 



Fig. 91 




Gejieral Tests, 

By reference to the journal of each day's work it will be observed 
that the first four days were occupied by preliminary tests, such as en- 
gine tests, hand-brake tests, train-resistance tests, etc. The Westing- 
house Brake Company, on the 5 th morning of the tests. May i 3 th, com- 
menced the general tests with a 50-car empty train — three stops on 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^^-^^^^^ 

level track, with their automatic air 
brake, 50 empty car train, resulting 
as follows : 



Table XX. — 50 Westinghouse Empty Car Train, 1887. 
Automatic Air Brakes. 



No. of Stop. 


Speed in 
Miles. 


Distance in 
Feet. 


Shock in 
Inches, 


Time in 
Seconds. 


Equivalent Distance at 
20 Miles and 40 Miles. 


521 

522 




186 
215 

588 


103 

7oj4 


9^ 

II 

17 


196 

233 


693 



These stops may be regarded as phenomenal in their shortness, which 
becomes all the more evident when we compare them with the best re- 
sults obtained in 1886. 

Table XXI. — 50 Westinghouse Empty Car Train, 1886. 
Automatic Air Brakes. 



No, of stop. 


Speed in 

Miles, 


Distance in 
Feet. 


Shock in 
Inches. 


Time in 
Seconds, 


Equivalent Distance at 
zo Miles and 40 Miles, 


621 


23,5 


424 


Not taken 


^iVz 


307 




611 


20.3 


354 


do. 


16 


340 




622 


40. 


922 


do. 


ii.yi 




922 


612 


40. 


927 


do. 


"^ 




927 



The brilliancy of the record, however, was completely spoiled by 
the fearful shock given at the rear end, the shdeometer moving, it will 
be observed, from 70 to 103 inches. The same train was then tested 
electrically, with the following results : 

Table XXII. — 50 Westinghouse Empty Car Train, 1886. 
Electric Application. 



No, of Stop, 


Speed in 

Miles, 


Distance 
in Feet. 


Shock in 
Inches. 


Time in 
Seconds. 


Equivalent Distance at 
20 Miles and 40 Miles. 


611 


21X 


160 


None. 


7 


139 




531 


23 


183 


do. 


8 


138 




6X2 


38 


475 


do. 


14X 




519 


532 


36>^ 


460 


do. 


14 




545 



^"^^^^-^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



Now comes the still more astonishing 
story. In these electrical stops the sHde- 
ometer never moved, and this with the 
same cars, the same leverages, and the same pressures, the only differ- 
ence being the time of application. With the shocks the application 
commenced on the rear car in from five to six seconds ; with the 
electrical application it was practically instantaneous on every car in 
the train. 

It will, perhaps, be necessary to compare the distances of these stops 
with other measurements to realize their full significance. Let us take 
the 138 and 139 ft. of the 20-mile stops. Telegraph poles are gen- 
erally spaced 33 to the mile, which allows a fraction of over 160 ft. 
between each pole. The stops were, therefore, made in 22 ft. less than 
the distance between 2 telegraph poles. Again, each of the Westing- 
house cars measured 37 ft., 8 in. from face to face of draw-bar; 133 
ft. would therefore be, measuring in freight car lengths, 3 car lengths 
and 25 ft. The hand-brake stop at the same point with the same cars 
was made in about 5^ telegraph poles' lengths, or a fraction over 23 
freight car lengths. This hand-brake efficiency is much greater than 
generally found in service, on account of the difference in foundation 
gear. 

The main results of the other 50-car trains are shown on the tables 
given herewith. 

Tabulated Stateme?its, 

The tables of this year are chiefly noticeable for the fi*eedom from 
shocks as compared with the previous year. This becomes all the more 
prominent when it is borne in mind that with one exception all the stops 
of 1887 were emergency stops with 50-car trains. An immediate result 
was a corresponding decrease in accidents ; no trucks were jumped 
from the tracks this year, no king-bolts sheared, and the trains were 
seldom broken in two. It may be noted that the Westinghouse train 
was equipped with the Janney coupler ; owing to the severity of its 
earlier shocks, two of these were broken during the trials. The 
Eames was equipped with the Boston coupler, which is of the vertical 
plane type ; two of these couplers were also broken during the trials. 



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THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^'''^ 



The Carpenter train was equipped with the 
ordinary link-and-pin draw-bar which was 
not wedged up during the great majority of 
the trials and suiFered no damage. The casualties due to the continuous 
brakes were inconsiderable as compared with last year, and show in the 
strongest possible way the benefits that may be obtained in freight-train 
service by more efficient brakes, together with the elimination of slack 
from the couplings. The pressure columns give interesting figures, and 
to get an intelligent appreciation of the work of the varoius competitors, 
is deserving of the most careful study. It will be seen that the middle 
car brake-beam force of the Carpenter brake is enormously high, con- 
siderably above the light weight of the cars, viz. : 

Average light weight of Illinois Central car, 27,351 lbs. 

Middle car brake-beam force 30,000 to 34,000 lbs. 

With the Westinghouse the reverse is the case. Average light 
weight of Pennsylvania Railroad car, 27,351 lbs. 

Middle car brake-beam force 19,000 to 23,000 lbs. 

The highest pressure carried by the Westinghouse Co. was in their 
stops 1823 and 1824. Unfortunately, the diagrams of these two stops 
were mislaid, and comparisons therefore cannot be made. Notwith- 
standing these low Westinghouse pressures, they nevertheless exerted 
sufficient power to slide wheels on dry rails. 

The Eames pressures were close to the hght weight of the cars, 
sometimes slightly exceeding it. The record under the heading of 
''■ wheel sliding " is not to be accepted as reliable, but merely as giving 
an approximate idea of the extent to which wheels were slid. As in 
1886, no wheels were flattened sufficiently to justify their removal. 
The Chicago, Burlington & Quincy Railroad Company, in purchasing 
the Eames cars after the contest, accepted the wheels without taking 
exception to any. The Illinois Central on receiving their cars back at 
Chicago condemned one pair on account of flat spots from sHding. 

Series B, 1887, plate VI., groups the competitors under each com- 
petition, ranking them in accordance with the shortness of stop, regard- 
less of other considerations. It will be seen that this year the hand 
brakes again succeeded in doing better work than one of the competitors. 



^""^'"'^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



In stops 3 and 4 of competition No. i, 

the hand brakes of the Pennsylvania, the 

lUinois Central, and the Chicago, Bur- 

hngton & Quincy cars all proved more efficient than the Hanscom 

automatic brake. Tests 621, 622, 623, and 624 of the Westinghouse, 

it will be observed, are service stops, vs^hile those of its competitors are 

all emergency stops. 

Towards the end of this table, plate VI., it v^ill be seen tests w^ere 
made with an eight-car passenger train made up of 8 old Chicago, 
Burlington & Quincy coaches, and also a train made up of 11 West- 
tinghouse freight-cars with the new triple, these proportions making 
trains of about corresponding weights. The difference in length of 
stop indicates the improvements that may be made in passenger train 
stops by the introduction of quicker acting triples. 

The last series of tests were made by the Westinghouse Company 
with some new triples constructed since the commencement of the 
tests wath the hope of overcoming the objectionable shocks in emergency 
stops, with their 50-car trai^i when operated atmospherically. Refer- 
ence to the slideometer column shows this has not been accomplished, 
though less than 30 cars composed the train. 

Owing to the various capacities of the competitors' cars, and conse- 
quent various light weights, a question arose early in the contest as to 
what should constitute a basis for the load of each in the mixed car 
train. 

In determining the efficiency of a brake the proportion of the brake 
power to the total weight of the train is an important factor. 

With equal velocities, the total energy of any moving body is pro- 
portional to its weight, and to obtain comparative resistances in destroy- 
ing the motion of trains by brakes, the force of the brakes should be 
proportional to the weight, and conversely the total load for a test train 
should be in proportion to the brake force. 

In order to get the best efficiency, it is the regular practice to make 
the brake power equal to the weight of the empty car. 

The competing companies at Burlington could safely do this, for they 
were always sure of a dry rail. The committee, therefore, decided 



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^""^'"'^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



that the brake power on the different cars 

should be taken as equal to their light 

weight, and that the cars should be 

loaded in proportion to their light weight, the load for the lightest being 

40,000 lbs. 

The Eames cars, weighing 25,600 lbs., were loaded with 40,000 lbs. 

The Carpenter cars, weighing 27,350 lbs., were loaded with 
42,800 lbs. 

The Westinghouse cars, weighing 30,577 lbs., were loaded with 
47,700 lbs. 

The ratio of brake power to the total load being 39 per cent, in 
each case. 

But as no restrictions were laid down regarding the leverage or pres- 
sures, each contestant still had considerable latitude as to what force 
should be used against the wheels to better any series of stops over those 
of a competitor. In looking over these tables, therefore, while the col- 
umn headed * ^ Weight, including Engine and Cars ' ' should be carefully 
noted, the pressure existing before the stops were made deserve equal 
consideration. 

Stops 1823 and 1824 of the Westinghouse, and 1623 and 1624 of 
the Carpenter, are deserving of special attention, as it will be seen that, 
in these stops, the gross weight of each train was made the same ; max- 
imum pressures were also used, each company endeavoring to make a 
minimum stop. 

Series C, 1887, plate VII., still further condenses the results. It 
deals only with the averages made by the Carpenter, the Eames, and 
the Westinghouse trains. It will be observed the Eames is the only 
train going through all the tests prescribed, both with its atmospheric and 
electric appliances. The results achieved by the Hanscom and Card 
brakes are not averaged, as their cars were withdrawn early in the trial. 

The Hanscom brake, on the eighth day of the contest, made its only 
stop run over the course. At the No. 4 stop the distance post w^as 
passed above the maximum speed allowed, and hand brakes were con- 
sequently called for. The brake was in a very unmanageable condition, 
and the fact that difficulties, which appeared trivial in testing a few cars. 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^""^'"'^ 



became insurmountable when multiplied 
by ^^x.y, was never better illustrated than 
in this case. No driver brake was used 
on the engine, which, of course, materially impaired the results. After 
this run Mr. Hanscom withdrew his brake from the contest. 

The Card Brake Company appeared on the ground with their 50 
cars and engine some days after the contest had commenced. The 
company used the American steam brake on its engine. On the ninth 
day they made their first run, but before the No. i post was reached 
the brakes went on automatically, and in stopping damaged the brake 
rigging of six or seven cars, which necessitated side tracking for repairs. 
On the twelfth day another trip was made ; the breakages to the 
gear again were considerable, showing that much had to be done 
before the apparatus could be successfiilly entered in such a contest. 
The owners withdrew from the contest after this run. A glance 
at the brake-beam pressure curves of the three leading competitors of 
1887, plates VIII. and IX., noting the rapid development of powder 
obtained by air, shows the difficulties and kind of competition the purely 
electric brakes have to meet. It will be difficult to get up a mechani- 
cal device winding a chain by means of friction wheels to develop power 
that will be as rehable and as quick as a straight pull or push on the 
levers actuated by air pressure. With any winding device the power 
has to be developed after application. With air pressure the power is 
stored ready to be shot oiF on the first application. 

Plate VII. shows the average results obtained by the three remaining 
competitors — Eames, Carpenter, and Westinghouse — in ^\^ different 
classes of stops and at two speeds for each class of stop. The classes 
of stops are as follows : 
1st. 50 empty cars, brakes applied by air. 
2nd. 50 do. do. electricity. 

3rd. 50 mixed cars, do. do. 

4th. 50 do. do. do. with slack shoes. 

5 th. 50 do. do. air. 

The numbers of each individual stop from which the average is com- 
piled, the name of the brake, the distance in which the stop was made. 



^""^'"'^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



corrected for uniform speed, which is also 
given on level and grade, the time in w^hich 
the brakes become fully applied and in 
which they were released, is also given. The weight of the train in 
tons 'of 2,000 lbs. and the percentage of that weight braked is given, 
and the pressures. The movement of the shdeometer indicates the 
severity of the shock experience in the rear car ; shocks above 1 2 
inches are considered as objectionable, and likely to injure stock and 
many classes of freight. 

Plate VII. shows the average results obtained first with 50 empty 
cars stopped by air, Westinghouse and Eames brakes. The stops made 
by the Westinghouse have been already alluded to. The shocks with 
the Eames brakes were considerably less than with the Westinghouse, 
but amounted to a maximum of 25^ inches. 

The next series of stops are those made with a train of 50 empty 
cars, the valves being actuated by electricity. All three brakes partici- 
pated in this class of stop. The results are noticeable for the complete 
absence of shock and for the remarkably small distance in which the 
Carpenter and Westinghouse trains w^ere stopped. The release with 
the Carpenter train, being effected by electricity, was remarkably quick, 
not exceeding i y^ seconds ; while the Westinghouse, released by air, 
averaged 36 seconds. The Eames release was in considerably less time 
than the Westinghouse. 

The next series of tests shown in Plate VII. are those made with a 
train of 50 cars, 33 loaded and 17 empty. Here again the Carpenter 
and Westinghouse brakes showed most remarkable results ; the trams 
weighing from i, 500 to 1,600 tons and 2,000 ft. in length, were stopped 
in an average of 171 to 182 ft. on a level grade at 20 miles an hour. 
These stops w^ere not accompanied by any excessive sliding of wheels, 
and by a very small movement of the slideometer, not exceeding ^-in. 
The Eames brake in these stops stopped the loaded train in a shorter 
distance than it stopped the empty train, showing that their method of 
varying leverage increasing with a loaded car produced a decidedly good 
effect in shortening the stop. The Carpenter and Westinghouse stops 
also show a slight improvement, but this was probably due to increased 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^""^'"'^ 



pressure, and, in the case of the Westing- 
house, to increased leverage. With the 
Eames train the pressure cannot be in- 
creased and the levers were unaltered during the trials. The Carpen- 
ter brake w^ould probably have shov^n even shorter average general stops 
at the No. 2, 3, and 4 posts had a larger pump and larger trainpipe 
been used, but the size of the pipe, ^ in., was insufficient to properly 
charge the leservoir at the rear end of so long a train, making four 
emergency stops in seven miles. This statement does not apply to the runs 
1,621 to 1,624 ; here the Carpenter train was allowed to wait after 
each stop to pump up any desired pressure. It will be observed, how- 
ever, that these stops are not computed in the averages on plate VII. 
They pertain too much to the nature of special efforts to score a record ; 
for similar reasons the Westinghouse stops 1,823 ^^^ 1,824 are excluded 
from the averages on this table. 

The next to last tests were made with a train of 33 loaded and 17 
empty cars, with the brake shoes placed one-half inch clear of the 
wheels. The Carpenter brake made a fair showing, the average 
distance in which the train stopped at a speed of 30 miles per hour 
on a level was 457 ft., the wheels on the empty cars were slid 
on an average from 140 to 225 feet, and there was a slight shock 
in the rear end, never amounting to more than ^ in. The best results 
were obtained with the Westinghouse brake and were very similar to 
those when the shoes were the ordinary distance from the wheels, and 
there was no shock. The stop with slack shoes was made with the 
two former brakes with electric application. The Eames stops, with 
slack shoes, were made by air, and the results are almost identical with 
those obtained under similar circumstances, but with the shoes the ordi- 
nary distance from the wheels ; the shock was moderate, never exceed- 
ing 7^ in., and the wheels slid about 400 ft. on the empty cars. 

Old Car Train Test, 

It was a matter of considerable regret that the endurance test had 
to be abandoned, and thereby allow opportunity to improve parts that, 
under an endurance test, would necessarily have remained unchanged. 



^""^'"'^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



The abandonment of such a test was all the 
more unfortunate, as it allowed those so dis- 
posed the opportunity of arguing with some 
plausibility that the stops made in 1886 and 1887 at Burlington did not 
represent stops attainable with trains in every-day use, that they were 
more in the nature of scientific stops with apparatus specially fitted up 
for making a record and that it was quite apparent that the many parts 
making up the continuous system would never give similar results after 
a few months' service. Serious doubts were even raised as to the 
practicability of the leverage used on account of the sliding of the 
wheels, not unusual or excessive in itself, and which is apparent when 
we state that not a single wheel was condemned in either 1886 or 
1887, at Burlington, on account of flat spots, but which was made 
prominent by the very nature of the tests. 



Note: Total Brake leverage for one Car 
1 to 7.2 
,.. Hand Brake 



^ 



_2_ 




~S Fig. 92 n 

Lieverages of Cars in Old Car Train. 

When it was suggested and decided that an old car train and engine 
running on the Burlington road should be tested over the course, all 
looked for the results with the keenest interest. This test would show 
the extent to which the equipment of the several competitors was 
especially prepared for the contest. A 25 old car train in a few 
days was collected and given a run over the course. If it was 
right to say that the brake companies' equipment had an advantage by 
being specially prepared for good work, so it would have been right to 
say that this old car train was such a one that would show the poorest 
possible result. Ten or twelve of the cars were taken off the Burling- 
ton shop bad-order track, where several of them had been marked for 
rebuilding. The shoes were in anything but good condition, some 
quite worn out and others with only a portion of their surface coming 
in contact with the wheel. The engine had but one reservoir supply- 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^'^^^ 



ing air to drivers and tank trucks, and only 
one of the tank trucks had power brakes. 
The leverage under the cars was the 
standard of the Chicago, Burlington & Quincy, and is shown in Fig. 92. 
The cars were fitted with iron brake-beams inside hung, the triples 
were those the Westinghouse Company sell with their freight-brake 
equipment and the ordinary Westinghouse engineer's valve with the 
Paradise extra pressure valve (owned by the Westinghouse Company), 
was used on the engine. Seventy pounds trainpipe pressure, the 
standard of the Chicago, Burlington & Quincy Railroad, was carried, 
so that in every respect the train represented the every-day practice of a 
train in regular service. 

On the following page will be found a record of this run with 25 
empty cars ; for comparative purposes we have placed also 25 mixed 



Fig. 93 



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Time in minutes 

car runs of the Westinghouse Company in 1886. The stops of this 
old car train are certainly remarkable ones. 

Some allowance should be made in favor of the Westinghouse trial 
train, owing to the fact of its being loaded, while the old train was 
empty. It will be seen that, with the exception of No. i stop, the 
old car train, in so far as distance is concerned, actually made shorter 
stops than the trial train. While the handicapping necessary to an 
empty-car train competing with a mixed-car train can be determined 
theoretically, we would draw the attention of those considering such a 
calculation to the difference in the empty and mixed car stops of 1887. 
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THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^""^'''^ 



observed that both the Westinghouse 
Company and Carpenter carried higher 
pressures in their mixed-train stops than 
with the empty train. 

It will be seen from this table that, with the increased pressures, 
the mixed loads only added to the length of the No. I empty stops 
some 50 or 60 feet. About the same figures are given at No. 3 stop. 
In comparing the No. 2 and No. 4 stops, it should be borne in mind 
the empty-train speed at these stops was 40 miles an hour, while the 
mixed was at 30 miles. 

Making due allowance for the condition of the old car train, its 
records seem to point in the strongest way that the stops at Burlington 
Fig. 94 ^ Eames 



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were not in any sense show tests, but what may be expected in every- 
day service. 

Down-Grade Run, 
No greater evidence of the advance in the brake problem in one 
year can be had than a perusal of the down-grade diagrams of the 
Carpenter and Eames brakes (Figs. 93 and 94). The Eames used 
its electric apparatus in making this run, and maintained, practically, a 
uniform speed. The 1887 down-grade runs are shown bv Figs. 93, 
94, and 95. These diagrams are constructed on the same plan as in 
1886, which is described on page 155. The distance run was some- 
what shorter in 1887 than in 1886, viz., i .926 miles instead of 2.021 
miles. The apparent irregularity in the speed line is due to the fore- 
shortening necessary in order to get so long a run in so short a compass 



6 




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THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^^^'^'^ 



rather than to any sudden variations in 
speed. The Westinghouse used its auto- 
matic air brakes, and, it will be seen, 
makes rather a worse showing than last year, and will not compare with 
its two electric competitors of 1887. In run 1423, fifteen retaining 
valves were set, which improved the latter part of the run, though still 
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The break-in-two tests are shown in the following table, and were 
participated in by the Eames, the Carpenter, and the Westinghouse 
brakes, the Hanscom and the Card having succumbed in the earlier 
test. Nothing noticeable occurred. Wedges were placed in the Car- 
penter train to wedge out the free link slack, inasmuch as with a break- 
in-two its brakes were applied by air in place of electricity. The train 
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train in place of a 25 mixed car train, and the parting was made in the 
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made to develop any tendency of the rear trains failing to stop and 
thereby colliding with the forward section. The stops were all suc- 
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electric connection was broken, which prevented the engineer from 
throwing brakes off the front end, a claim made by the Carpenter in 
common with the Eames, 







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THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^'''^ 

Middle Car Diagram, 
The most interesting and instructive 
records obtained during the trials were 
the middle car diagrams. We reproduce on plates VIII. and IX., 
and Figs. 96 to 99, a few typical stops of the principal competitors. 
A description of the reading of these diagrams will be found on page 
135. In examining these diagrams, particular attention is directed to the 
fact that the vertical scale of the pressure curve of each competitor is 
different. This difference was an unavoidable one, caused by the vari- 
ations in truck leverages, cylinder leverages, and, in some cases,, the 
bell-crank connection to the recording apparatus. 



Pis. 96 




->l 



1918T7 16 15 14 13 12 



Seconds 
Middle Car Diagram, Eames, 1886. 

The scale is also given on each sheet, so that there need be no mis- 
apprehension as to the relative value of the vertical stress line. The 
faults incident to slow application have already been referred to. The 
extent to which electric apphcation has improved this is clearly seen by 
comparing the Westinghouse and the Eames 1887 automatic stops with 
their 1887 electric stops. Having established the importance of instan- 
taneous apphcation on each car, it next becomes important to get 
maximum pressure of shoes against the wheels in the shortest possible 
time. If we look at the Eames diagrams. Figs. 96 and 97, it will be 
observed that the vacuum stops of 1886 and 1887 show but little 
difference in commencement of apphcation : 

Stop No. 

1886 . . ^21 22.4 250 feet. 8 



^ , Brakes begin to ap- No. of seconds Stop, 
ply on 25th car. elapsed. 



1887 



521 
711 



22.4 250 tect. 8 437 

21.75 213 feet. -lYi 364 



I 



Automatic Air 1886 

50 Empty Cars 
General Test Ko. 1—2 




M. C. B. Brake Tests, 1886 & 1887 

MIDDLE CAR DIAGRAMS 

Sbowiag 

Pressure on oil ISrake Shoes ofonc Car,- Speed of Train, Dls 

Eun after Application ofBrakcs and Lcnetli of Time Intervening 

een Application of Brakes on tbc Engine and on the Middle Car 

Westiughouse Air Brake 




^""^'"'^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



The stop, however, is much shorter ; 
this is due to the greater pressure against 
the wheels obtained in 1887, viz.: 24,- 
000 lbs. as against 9,500 lbs. The development of power with the 
Electric Eames shows the same exceedingly slow pressure curve, which 
clearly accounts for its not doing the work of its competitors, the 
Westinghouse and the Carpenter. 




•173€16 15 14 13 12 



Middle Car Diagram, Eames, 1887. 

An examination of the Westinghouse diagrams. Figs. 98 and 99, is 

equally interesting. A marked improvement is shown in the automatic 

brake of 1887 : 

Brakes begin to ap- 
ply on 25th car. 

364 feet. 

1 10 feet. 

The work of the improved triple valve becomes quite apparent here, 
but the stress hne also shows that the importance of a rapid develop- 
ment of power has been observed. No clearer demonstration of the 
extent to which the brake company has realized this can be had than 
by a comparison of the stress curves of stop 1,614 ^^ 1886 and stop 
1,724 of 1887, plate VUL The curves with the electric application 



1886 
1887 



Stop No. 
1,61 I 



Speed. 



19.25 



No. of seconds „ 

elapsed. ^' 

13 418 

4.25 215 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^"^'''^ 



of the Westinghouse are the same as their 
automatic application, the shorter stops 
being due solely to quicker application. 
Before leaving this subject it is instructive to note that in stop i , 6 1 1 of 1 8 8 6 
no development of powder against the wheels is shown in this 25 th car 
until I 3 seconds have passed. If we now refer to the journal of tests for 
1886, we will find under its proper column that the time the ^* brakes 
begin to apply " on the 50th car is about 8 seconds ; that is to say, the air 
began to go into the cyhnder of the 50th car in 8 seconds from the 
stop signal, and it developed its maximum cylinder pressure in 1 1 
seconds. The air from the auxihary reservoir of the 25th car must 
have gone into its cyhnder earlier than on the 50th car, and yet no 

Fig. 98 



18 1716 16 14. 13 



Middle Car Diagram, Westinghouse, 1886. 

pressure is shown against the wheels until 1 3 seconds have elapsed. 
Clearly, then, the air, which first goes into the cylinder, has a function 
to perform before it can develop pressure against the wheels. Piston 
frictional resistance has to be overcome, cylinder springs compressed, 
slack in foundation gear has to be taken up, brake beams stretched taut, 
and the time necessary to do this in the 1886 tests was stretched out 
to unreasonable Hmits by the slow development of power. The action 
of the triples would also ,have some influence. A marked improvement 
in this respect appears in the 1887 tests. 

The Carpenter diagrams (see Plate IX.) show very clearly how the 
stops were effected. At both the 20 and 40 miles speeds the maxi- 
mum brake-beam pressure was reached generally in about 2 seconds 



^""^'"'^ Air Brake Tests 



THE 

BURLINGTON 
BRAKE TRIALS 



from the commencement of the appHca- 
tion, and as the appHcation is almost sim- 
ultaneous with the stop signal, the stop 
is correspondingly good. The accurately fitted foundation gear of this 
brake resulted in a very short piston travel, which doubtless had much to 
do w4th the excellence o1 the stress curve. It is a question, however. 




49ii3rUes 



11 10 9 

Middle Car Diagram, "Westinghouse, 1887. 

whether even this rapid development of stress appHcation might not be 
bettered by a quicker admission from the auxiliary reservoir to the cylinder. 
By reference to Plate IX., of the American brake, it will be observed 
the maximum application is reached instantaneously with the application 
itself While such an application pertains doubtless too much to a 



THE 

BURLINGTON 
BRAKE TRIALS 



Air Brake Tests ^^^^^-^^ 



hammer blow, the endeavor should be 
to reach the maximum stress line in one 
second's time, which would bring about 
shorter stops than those shown with the Carpenter brake. 

While the Committee were not prepared to make any definite recom- 
mendation at that time as to what freight train brake should be generally 
adopted, the information derived from these recent tests pointed to two 
conclusions : 

First — That the best type of brake for long freight trains is one oper- 
ated by air and in which the valves are actuated by electricity. 

Second — That this type of brake possesses four distinct advantages : 

(tf) It stops the train in the shortest possible distance. 

(^) It abohshes shocks and their attending damage to equipment. 

(r) It releases instantaneously. 

(^) It can be graduated perfectly. 

The further question, as to whether electricity was a sufficiently 
reliable element to use in freight train service, was one that could only 
be determined by experiment ; but the benefits derived from electricity 
were so manifest that the experiment was well worth trying. In view 
of the foregoing and of the improvements that were being made, the 
Committee recommended that the subject of Automatic Freight Train 
Brakes be continued for further investigation. 



)0( 



M. C. B. Brake Test, 1886 and 1887. 
MIDDLE CAR DIAGRAMS. 



■e on all brake shoes of on 



and length of time Interventnar between application 



ipeed of train; distance run after application of brakes; 



of brakes to engine and to middle ct 



Carpenter Electric Air Brake 
Emergency Stop 

50 Emiity Car Train. I, 




Eames Automatic Vacuum Brake 
Emergency Stop 

50 Empty Car Traiu. 




WESTINGHOUSE FREIGHT TRAIN TEST. 

As stated in the conclusion of the 1887 report of the Air Brake 
Committee to the Master Car Builders' Association, the various com- 
peting Brake Companies were loath to accept the results of the Burling- 
ton trials as final. 

It is true that the buffer brakes practically went out of existence 
after these trials, but the companies furnishing continuous brakes, 
although disturbed and chagrined at the very discouraging results of the 
tests, were still confident that they were following the right track and 
determxined to develop their devices so as to overcome the shocks which 
were so dangerously manifest all during the Burlington trials. 

The Westinghouse Company, in particular, was not willing to let 
the results so obtained stand uncorrected, and Mr. George Westing- 
house, — who is in reality the '^ Father of Air Brakes " in that his in- 
vention in this line was the first practical device of its kind, and whose 
determination and perseverance has brought about the whole art of air 
breaking, — was thoroughly convinced that his invention could be made 
to control a 50-car train without the aid of an electrical attachment. 
Although the results of the trials just finished pointed with apparent 
certainty to the conclusion that such attachment was indispensable, Mr. 
Westinghouse at once set about making certain changes in his apparatus 
which would quicken the serial application of the brake to such an 
extent that the application on the last car would occur before the slack 
could run in. These changes consisted of enlarging the trainpipe from 
one inch to one and a quarter inches ; and also in making changes in 
the triple valve whereby the quick-action feature was greatly increased 
through larger passages and more sensitive valves. In this manner the 
time of application through a 50-car train was reduced from six seconds 
to less than three. This was demonstrated upon the same train which 
was used in the Burlington tests in 1887, which was made up of 50 
cars 38 ft. 4 in. long, of 60,000 lbs. capacity ; the total length of 
the train was 1,900 feet and the total weight 2,000,000 lbs. After 
the above mentioned demonstration convinced the Westinghouse Air 
Brake Co. that the problem had been solved, this train was sent on a 



WESTINGHOUSE 
FREIGHT TRAIN 
TESTS 



Air Brake Tests ^"^''^^ 



tour through some of the principal cities of 
the country in each of which it gave two 
series of trials, which were attended by 
many hundreds of railway managers, press representatives, prominent 
citizens, and professors and students of technical schools. These trials 
were made during October, November, and December of the same year 
as the last Burlington trial — 1887. The following table gives the gen- 
. eral results of the trials which were in most of the cities divided into ten 
different tests. The results were widely published in all the technical 
papers. One engine was used in all of these tests, except those at St. 
Paul, where two were used. In the table, all fractions of miles and 
seconds have been omitted. 

Description of Tests, 

1 . Emergency stop, train running 20 miles an hour. 

2. Emergency stop, train running 40 miles an hour. 

3. Applying brakes while train is standing still, to show quickness 
of application. 

4. Emergency stop, with passengers aboard ; speed, 40 miles per 
hour. 

5. Service stop, and time of release. Showing the kind of stop 
made when a sudden stop is not necessary, and how promptly the 
brakes can be released. 

6. Hand-brake stop, made at 20 miles an hour, with five brakemen 
at their posts (at Buffalo there were seven brakemen). 

7. Breaking train in two. 

All the above stops were made with the braking power so low that 
it would not slide the wheels of empty cars in regular service. By us- 
ing greater power, quicker stops could be made, but there would be 
more or less sliding of wheels, and it was not thought that the advan- 
tage gained would be enough to make up for the damage done in freight 
service. 

8. Train running 20 miles an hour ; the brake leverage having been 
increased to give the quickest stop possible. 

9. Train running 40 miles an hour ; leverage as in No. 8. 



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FREIGHT TRAIN 
TESTS 



Air Brake Tests ^^^^^-^^ 



lo. A train of 20 freight cars and a 
train of 1 2 ordinary passenger coaches 
were run alongside of each other, on 
parallel tracks, and the brakes applied at the same time. This test 
showed the relative stopping power of the old and the new 
brakes. 

As a result of this train's now famous tour, the Committee of the 
M. C. B. Association on Freight Train Brakes reported to the meeting 
of that Association held at Alexandria Bay, N. Y., June 12th, 13th, 
and 14th, 1888, as follows : 

^* In our report to the convention last year the main conclusion we 
arrived at was that the best type of brake for freight service was one 
operated by air, and in which the valves were actuated by electricity. 
Since that time your Committee has not made any further trial of brakes, 
but the aspect of the question has been much changed by the remark- 
able results achieved in non-official trials which have taken place in 
various parts of the country, and have been witnessed by many of the 
members of this Association. These trials show that there is now a 
brake in the market which can be relied on as efficient in any condition 
of freight service. 

^ ' The present position of the freight train brake is briefly as follows : 

^^ First — Brakes can be, practically speaking, simultaneously applied 
without electricity throughout a train of 50 freight cars. 

'^ Second — Other inventors are working at the problem of making 
an air brake which will be rapid in action and suitable for service on 
freight trains. We also understand that inventors are working at buffer 
and electric friction brakes, but we have no reason to hope that brakes 
on these principles can successfully compete with air brakes. 

'^ In view of these conditions, your Committee does not recommend 
the adoption of any particular brake, but considers that a freight-train 
brake should fulfill the following conditions : 

** First — It shall work with air of 70 lbs. pressure. A reduction 
of 8 lbs. shall set the brakes lightly, and a restoration of pressure shall 
release the brakes. 

'^ Second — It shall work without shock on a train of 50 cars. 



^""^''^^ Air Brake Tests 



WESTINGHOUSE 
FREIGHT TRAIN 
TESTS 



^* Third — It shall stop a train of 50 
empty freight cars when running at 20 
miles per hour within 200 feet on the level. 

'^Fourth — When tried on a train of 50 cars it shall maintain an 
even speed of fifteen miles an hour down a grade of 53 ft. per mile 
without variation of more than five miles per hour above or below that 
speed at any time during the descent. 

** Fifth — The brake shall be capable of being applied, released, and 
graduated on the whole train by the engineer, or without any assistance 
from brakemen or conductor. 

''Sixth — -The hose coupling shall couple with the present West- 
inghouse couplmg. 

*' We recommend that all freight cars fitted with such a brake shall 
be marked ' Air Brakes ' on each side of the car, near the top. The 
Committee further recommends the use of iron or steel brake-beams, and 
that the subject of the best form and proportion o^ brake gear and the 
selection of a standard solid brake shoe for use with metallic brake- 
beams should be entrusted to a committee appointed for the purpose." 

(Signed.) G. W. Rhodes, 

George Hackney, 
John S. Lentz, 
D. H. Neale. 



/v( 



THE KARNER TESTS. 

In the early part of September, 1892, comparative tests of quick- 
action brakes were made at Karner Station on the New York Central 
& Hudson River R. R. One hundred standard 60,000 lbs. capaci- 
ty box-cars, built by the Buffalo Manufacturing Co., and fitted with 
the Gould Coupler, were prepared for two trains. One train of fifty 
cars was equipped with the New York Air Brake reservoirs, eight-inch 
cylinders and No. 2 triples. The other train of fifty cars was equipped 
with the Westinghouse Air Brake reservoirs, eight-inch cylinders and 
triples with their standard springs of .073 in. in diameter. 

The trainpipe was i i^ in. diameter, with Westinghouse hose con- 
nections and cocks for both trains. 

All of the cars were reweighed with the exception of three of the 
Westinghouse train which did not arrive in time to be weighed. The 
loss from the weight marked on the cars averaged from 850 to 1,000 
lbs. 

The leverages were such that the ratio of the piston pressure to the 
braking pressure on the wheels, figures i to 61^. With 60 lbs. of air 
in the cylinder, the pressure on the wheels figured 19,500 lbs. — about 
70 per cent, of the weight of the empty car. The loss of pressure 
from release springs or friction of the connections was not considered. 

The trucks were the heavy Buchanan diamond pattern, hollow iron 
brake-beams with inside hung cast-iron shoes. The shoes were 13^^ 
in. long by 31^ in. wide, equal to about 44 sq. in. for 60 lbs. of air 
in cylinder. 

The journals were 41^ in. x 8 in.; wheels 33 in. in diameter, 
weight 560 lbs. 

The cars had been in service running between Buffalo and New 
York and Buffalo and Boston for nearly three months, until collected at 
Karner for the trials, the shoes being well worn to the wheels. 

A few of the reservoirs were filled with water to ascertain their cub- 
ical contents. The older Westinghouse cyhnders ranged from 1,610 
1,618 cu. in., the recent ones cast at Wilmerding and on the cars of 
the Westinghouse train, ranged from 1,620 to 1,630 cu. in. The New 



%4J 




< 



< 






^""^''^^ Air Brake Tests 



THE KARNER 
TESTS 



York reservoirs tested, ranged from 1,632 
to 1,640 cu. in. The trainpipe and 
hose for each car averaged 640 cu. in. 

Three cars of each kind of brakes were piped with ^-in. pipe for a 
gauge each, on the trainpipe, reservoir, and cyhnder ; also with connec- 
tions so that pipes could be run to the indicators on the recording me- 
chanism in a special car called the Dynagraph car. 

Each company sent eight gauges for its respective equipment ; the 
ninth required was one fitted with electric contacts for the cylinder of the 
25th car, and was to be used for both trains. The gauges of both 
brake companies were of the same manufacture and were corrected by 
comparing them with the test gauge at the West Albany shops. 

Mogul locomotives with 6 drivers 64 in. in diameter, pony-truck, 
cylinders 19 in. x 26 in., carrying 140 lbs. of steam, were fitted with 
tripping devices shown in Fig. 100, for automatically applying the air, 
by tripping blocks placed in the tracks directly under the signal banner 
for shutting off steam. 

To make the tripping device upon the locomotive for automatically 
applying the air, a tee was inserted in the trainpipe near the engineer's 
valve, and from it a pipe was carried down underneath the cab to 
within 18 in. of the track ; a plug cock being fitted in this pipe near 
the engineer's valve, so it could be opened or closed by the engineer in 
case any accident should occur to the pipe. Below the cab, in the 
lower part of this same pipe, another plug cock was arranged with a 
spring attached to the handle, so the tension of the spring would hold 
it open. A bracket from the engine frame carried the tripping lever, 
the upper end forming a hook which held the handle of the cock when 
the latter was closed. The lower end of the tripping lever was about 
2 in. above the top of the rail. 

To the lower end of the tripping device pipe a union was attached 
in which the diaphragms could be placed for those tests requiring their 
use. Precaution was taken to have the tripping lever and its bracket 
entirely independent of the brake gear below the cab, so in case any 
accident occurred to it, it would not be Hkely to interfere with the 
W^orking of the air in the proper mechanism. 



THE KARNER 
TESTS 



Air Brake Tests ^""^''^^ 



Each engine was equipped with this 
special device. The locomotives were 
just out of the repair shops. One loco- 
motive was also piped for the use of the small diaphragms required to 
test the sensitiveness of the emergency valve. 

A Boyer speed recorder was also put in the same engine to assist the 
engineer in running at the desired speed ; the engineer of the train on 
the adjacent track to run at the same speed by keeping abreast of the 
other. 

The devices for determining the actual speed of each train were 
electrical trips placed eighty-eight feet apart in each track, as described 
later. 

Each locomotive was equipped with the usual Westinghouse brake 
mechanism ; the pump being 8 in. in diameter, and the main reservoir 
26^ in. by 34 in., having a capacity of 16,500 cu. in. 

To ascertain the intervals of time from the opening of the engineer's 
valve to the application of the air on the first car and on the fiftieth car, 
the recording mechanism of the Dynagraph car was fitted up with two 
pressure indicators and a battery of electro-magnetic pens. 

Two of the electro-magnetic pens were connected to a chronometer 
for making the chronograph records upon the moving paper. One pen 
was connected to the engineer's valve on the locomotive and another 
pen to a telegraph key, so that any other signals desired might be 
recorded. A small electric motor run by a storage battery was geared 
to shafting, driving the feed rolls and winding drums of the record- 
ing mechanism, and a circuit closer enabled the mechanism to be run 
when desired. The paper was 20 in. wide and usually ran at a speed 
of 1.4 in. of paper per second. 

A tee below each indicator connected two branch pipes having cocks, 
one branch leading directly to the trainpipe of its respective car ; the other 
branch by a tee was further subdivided, one branch connecting with the 
reservoir and the other with the cyHnder of the same car. Connec- 
tions with the first and fiftieth cars of the train with the recording 
instrument were thus provided for during the standing tests, described 
later. 



J 




Fig. ioo.— tripping DEVICE USED AT KARXER TRIALS. 



^""^''^^ Air Brake Tests 



THE KARNER 
TESTS 



The 50-cars were divided into two 
sections of 25 cars each and placed on par- 
allel tracks, with one track intervening for 
convenience of observation. The twenty-fifth and twenty-sixth cars 
were connected by i i^ in. pipe 27 ft. in length, and 4 lengths of hose 
connections. The first, twenty-fifth, and fiftieth cars of each train were 
provided with gauges. The first and fiftieth cars were placed nearly 
opposite on the parallel tracks; the first car was attached to the locomotive 
and the fiftieth car was attached to the Dynagraph car, and pipe con- 
nections from the first and fiftieth cars were made to the indicators above 
mentioned. Similar diagrams had not before been obtained, and formed 
a fitting supplement to the invaluable Burlington tests, which were the 
inception of automatic freight brakes for long and heavy trains. The 
present diagrams not only showed the progress which had been made 
since those trials, but confirmed, in a comprehensive way, that progress 
must follow^ closely along the lines there well defined. 

Previous to the standing tests on. September 6th and 7th, the trains 
were charged with air, the trainpipe tightened, the leaks in the gaskets or 
sand holes of reservoirs, cylinders, or triples were noted but not repaired. 
None of the tripple valves were taken down, excepting one fi*om each 
brake, and these were found quite free from grit and well lubricated for 
having had three months service. 

The engineers and crews were from the regular freight service, and 
while familiar with handling 2 5 -car trains with air, this was their first ex- 
perience wdth 50-car trains equipped with air brakes, and both engineers 
expressed surprise at the tightness of the train line in comparison with 
shorter trains. 

The following programme stating the general character and num- 
ber of the tests was printed for the guidance of employees and observers : 
Programme — New York Central & Hudson River Railroad Co. 
Trials of the Westinghouse Air Brakes and the New York Air Brakes 
for Freight Trains, at Karner, Sept, 8, g, and lOy l8g2. 

Tests to commence at 9.00 A. M. each day, and to be practically 
the same as those recommended by the Committee on Air Brakes of the 
M. C. B. Association, 



THE KARNER 
TESTS 



Air Brake Tests P^se24o 

Condition of Tests, 
50-car trains. 
Trainpipe pressure, 70 lbs. 



Piston travel, 5 in. to 7 in. 

Standing Tests, 

Locomotive and Dynagraph car, to be side by side on parallel tracks. 

25 cars attached to the locomotive, and 25 to the Dynagraph car. 

The air hose of the 25th and 26th connected. 

The first and fiftieth cars connected by air pipes to the instruments on 
the Dynagraph car. 

Running Tests, 

The trains of 50 cars w^ill be placed on parallel tracks and run side 
by side at same speed. Locomotives shut off at signal-post. Air auto- 
matically applied by tripping block. 

Schedule of Tests, Testing Trainpipe, 

1. Trainpipe charged w^ith 70 lbs. of air. All brakes cut out, 
pump shut off. Record of pressure to be taken at the end of five min- 
utes. 

2. Trainpipe recharged to 70 lbs. Service application to see time 
required for reduction of trainpipe pressure fi-om first to fiftieth car. 

3. All brakes cut in. Time of reduction in pressure of trainpipe 
from first to fiftieth car. Service application and release. (^Note — 
Service application to be 20 lbs, reduction in trainpipe,^ 

4. Same as No. 3, except emergency application. (^Note — 
Handle of engineer'' s valve in emergency notch one second — for emergency 
application, ) 

5. Time of development of pressure in cylinders from first to fif- 
tieth car. Service application and release. 

6. Same as No. 5. Emergency application and release. Repeated 
three times. 

7. Time of development of pressure in cylinders, the fifth, sixth, 
and seventh cars cut out. Emergency application and release. Re- 
peated three times. 



^^^^^^^ Air Brake Tests 



THE KARNER 
TESTS 



8. (Special and optional.) Same as 
No. 7, except the fifth to the tenth car 
inclusive cut out. 

Graduation Tests. 

9. A reduction of 8 lbs. in the trainpipe pressure to be made ; 
then at one-minute intervals, further reduction of 4 to 6 lbs. to be 
made until reservoirs and cylinders are equalized. Repeated tw^ice. 

10. Service application, 15 lbs., to be admitted into cylinders, 
pressure noted then at the fifth, tenth, and fifteenth minutes. 

1 1. Same as No. 10, except all the air to be exhausted from train- 
pipe by emergency applications. 

Release Test. 
(Boiler Pressure, 160 Lbs.) 

12. 70 lbs. in trainpipe, all the air will be discharged by an 
emergency application. A pressure of 90 lbs. will then be maintained 
against a diaphragm ^ in. thick, perforated with -^\-in. hole, and a 
record taken of all brakes which release in thirty minutes. 

1 3 . Test to determine the sensitiveness of the emergency valve. 
The first and fiftieth car will be cut from the train and hose connected; 
70 lbs, trainpipe pressure will then be discharged through a diaphragm 
perforated with 3^-in. hole. Each car to be tested singly, if desired. 

14. Test to determine time of charging one auxiliary reservoir and 
trainpipe. Note time of changing reservoir to 70 lbs. 

Record of Tests. 

Test No. i. — In testing the trainpipes before the tests proper, 
each train only lost a pound in 'kxt minutes. 

Test No. 2. — Brakes cut out. Time required for reduction of 
trainpipe pressure from first to fiftieth car. The engineer placed the 
handle of the brake valve in the service notch for three and a half 
seconds and reduced the trainpipe pressure 20 lbs. by gauge. 

The equalizing valve rendered the action much slower, discharging 
air for several seconds after he had placed the valve upon lap, prevent- 
ing an emergency action of the triple valves. 



THE KARNER 
TESTS 



Air Brake Tests ^^^^^^^ 



For these 50-car trains, 1,940 feet 
long, the air head in the standing tests 
was 51^ lbs. The constant head was 
not observed until all the tables were compared, the diagrams were then 
re-examined and the time of the constant found to be practically the 
same in each train. The wave of air in the release from the high 
reservoir pressure traveled from the first to the fiftieth car in 6 to 10 
seconds ; some diagrams only showed from 3 to 4 seconds. 

Test No. 2. — Table XXVI. — New York Air Brake Trainpipe. 

Pressure in Pounds^ 'Time Intervals in Seconds. 



Seconds 





6/2 


19 


^S/2 


40 


First Car 


69.30 


63.00 


57-75 


54.60 


52.50 


Fiftieth Car ... . 


69.30 


68.25 


63.00 


59-85 


55-70 


Difference 


0.00 


5-25 


5.25 


5.25 


2.60 



Westinghouse Brake Trainpipe. 



Pressure in Pounds^ Time Intervals in Seconds. 



Seconds . . . , 





8 


18 


28 


38 


46 


50 


60 














Released. 






First Car . . 


70-35 


63.00 


58.80 


54.60 


52.50 


52.50 


67.60 


66.15 


Fiftieth Car . 


70.35 


68.25 


64.05 


58.80 


55-65 


54.60 


54.60 


59.85 


Difference . . 


0.00 


5-^5 


5-25 


4.20 


3.15 


2.10 


3.00 


6.30 



Test No. 3. — All brakes cut in. Time apphcation of the pressure |i 
of the trainpipe from the first to the fiftieth cars, service application 
and release. In the tests of both trains, i to 3 seconds more time 
was required before a reduction was effected in the fiftieth car than in 
test No. 2. This discrepancy was due to the pressure being higher in 
the first car than the fiftieth — a flow of air still going to the latter 



THE KARNER 
TESTS 



^^^^^^-^ Air Brake Tests 

car — and the increase of trainpipe vol- 
ume from cut-out cock to triple, to be 
reduced. 



Test No. 3. — Table XXVII. — New York Air Brake Train. 

Pressure in Pounds, Time Intervals in Seconds. 



Seconds . . = 





II 


21^ 


36X 


48>^ 


55;^ 


65 


First Car 

Fiftieth Car ... . 
Difference 


70.35 

68.25 

2.10 


61,95 
68.25 

7.30 


57.75 
63.00 

5-75 


52.50 

57.75 

5.25 


Released. 

52.30 

54.60 
2.10 


63.00 


55.10 









Westinghouse Air Brake Train. 

Pressure in Pounds^ Time Intervals in Seconds. 



Seconds . . 





9 


19 


29 


39 


49 


59 


69 


79 


89 


99 


First Car . . 


70.35 


63.00 


58.80 


54.60 


52.50 


51.45 


Released 
50.40 


63.00 


61.40 


60.90 


60.90 


Fiftieth Car . 


69.30 


69.30 


64.05 


59.85 


55.65 


53.55 


52.50 


54.60 


57.75 


57.75 


58.80 


Difference. . 


-1.05 


6.30 


6.25 5.25 


3.15 


2.10 


2.10 


8.40 


3.65 


3.25 


2.10 



In the New York train one car did not fully apply. 

Emergency Application. 
Test No. 4. — New York Air Brake Train. 

Train line in first car 70.4 lbs., fiftieth car 69.8 lbs. 

In 0.16 seconds from movement of engineer's valve the pressure 
commenced to fall in the first car, and in i . 8 seconds it was down to 
37.8 lbs. 

In 3.31 seconds the pressure commenced to fall in the fiftieth car 
and in o. 17 of a second, or 3.32 seconds from the first car, was down 
to 48.3 lbs.; first car fell to 37.8 lbs., then rose to 47.3 lbs. in 3.64 
seconds. 

The release was not ordered until 38 seconds after the application. 



THE KARNER 
TESTS 



Air Brake Tests ^"^^^^^ 

first car reading 47.3 lbs., and in 6 
seconds first car read 62 lbs.; in 88 
seconds from release, trainpipe pressure 
read in first and fiftieth cars 63 lbs. 

Test No. 4. — Westinghouse Air Brake Train. 
Trainpipe pressure in first car 69.3 lbs., and fiftieth car 68.3 lbs.; 
in 0.15 of a second after the movement of the engineer's valve the 
pressure began to fall in the first car and in i . 8 i seconds w^as dow^n to 
38.85 lbs. In 2.71 seconds the pressure commenced to fall in the 
fiftieth car, and in 2.86 seconds, or 2.71 seconds from the first car, 
w^as down to 51.45 lbs. The brakes w^ere released in 18 seconds, 
the fiftieth car releasing in 4.3 seconds later. 

Test No. 5. — Table XXVIII. — New York Air Brake Train. 

See Diagram, Plates Nos. X. and XI. 

In .8 of a second from the movement of engineer's vaive pressure commenced in the first car. 

Pressure in Pounds^ 'Time Intervals in Seconds. 



Seconds 


6.8 


9 


13 


20 


30 


40 


50 


60 


Released. 


First Car 

Fiftieth Car 


4-7 
0.0 


3-1 


16.8 

5.65 


24.2 
18.9 


34.6 
28.4 


37.8 
34-7 


41.5 

37.8 


42. 

34-7 


75 Sec. 
81 do. 



Westinghouse Air Brake Train. 

In .7 of a second after the movement of the engineer's valve the pressure 

commenced in the first car. 

Pressure in Pounds.. Time Intervals in Seconds. 



Seconds 


6.8 


10 


20 


30 


40 


50 


60 


Release Occupied, 


First Car 

Fiftieth Car .... 


6.3 
3.2 


II. 6 

4.2 


24.2 
11. 6 


36.3 

22. 


38.8 

28.3 


37-5 
31-5 


33.6 

28.4 


7 Seconds. 
6>< do. 



Test No. 6. — The engineer, in trying to open the brake- valve to 
the emergency notch i second, as directed, was more deliberate than 
he w^ould be in making the emergency application when runnmg ; 0.05 
to 0.06 of a second is the possible time from the locomotive to the fir«st 
car. The automatic trip indicated 0.04 to 0.05 of a second. 




Plate X 
New York Brake. Test Ko. 5. 




Tlate XI 
New York Brake. Test No. 5. 



^"^^^^-^ Air Brake Tests 



THE KARNER 
TESTS 



The diagrams and tabulations of test 
No. 6 show at a glance the distinctive 
character between the action of the two 
triples in the emergency application, each being constructed upon a 
different theory regarding the best application of air for such uses. The 
New York applies rapidly up to 40 lbs., then more slowly, equalizing 
at a higher pressure of i or 2 lbs., than is usual. Three seconds is 
about the time consumed per car in attaining the maximum pressure. 

The Westinghouse applies rapidly, reaching in about i second the 
maximum pressure per car, which for the same trainpipe pressure is 
I to 2 Ibsc lower than the New York. The slower application of the 
New York does not permit of reaching a maximum pressure of 5 5 Ibso 
in 3 ^ seconds on the fiftieth car, as is the case with the Westinghouse. 

Test No. 6. — Table XXIX. — New York Air Brake Train (Three Trials) 
See Diagram in Plate No. XII. 



No. of 
Trial. 


Trainpipe 
Pressure. 


Time of First 
Movement of 

Engineer's 

Valve to First 

Car. 


First Car Time 

and Maximum 

Pressure. 


Fiftieth Car Time of 

Application and 
Maximum Pressure. 




Car. 


Seconds. 


Seconds. 


Pounds. 


Seconds. 


Pounds. 




Firsts 


Fiftieth . 




First . . 
Second . . 
Third „ . 


69.3 


69.3 


0.25 
0.24 
0.28 


3.6 

3.2 
3.2 


58.80 

59.85 
61.95 


3.38 
3.30 
3.30 


6.20 

6.20 
6.20 


5565 

57.75 
58.25 



Westinghouse Air Brake Train (Three Trials). 
See Diagram, Plate No. XIII. 



No. of 
Trial. 


Trainpipe 
Pressure. 


Time of First 
Movement of 

Engineer's 

Valve to First 

Car. 


First Car Time 

and Maximum 

Pressure. 


Fiftieth Car Time of 

Application and 
Maximum Pressure. 




Car. 


Seconds. 


Seconds. 


Pounds. 


Seconds, 


Pounds. 




First. 


Fiftieth. 




First . . . 
Second . . 
Third . . . 


68.3 


68.3 


0.30 
0.20 
0.20 


1.30 
1.20 
1.20 


57.75 
58.75 
57.75 


2.9 

2.8 

^.75 


3.8 

3.7 

3.65 


55.65 
55.65 
55.65 









In the three trials of No. 6 test with the Westinghouse train one car leaked off. 



THE KARNER 
TESTS 



Air Brake Tests ^^^^^^^ 



Test No. 7. 
Time of development of pressure in 
cylinders, the fifth, sixth, and seventh 
cars cut out» Emergency application and release. Repeated three 
times. 

New York Train. 

Test No. 7. — First trial. First car applied in .2 seconds. Fif- 
tieth car applied in 3.7 seconds. First car reached a pressure of 60.9 
lbs. in 3 seconds. Fiftieth car reached a pressure of 57.8 lbs. in 6.5 
seconds. 

First car released at 58.8 lbs. and the fiftieth car released in 7^ 
seconds after the first. 

Test No. 7. — Second trial, failed. Trainpipe, 69.30 lbs. in the 
first car. Trainpipe, 70.35 lbs. in the fiftieth car. 

Test No. 7. — Third trial, failed. 

Test No. 7. — Fourth trial, failed. Trainpipe pressure 69.30 lbs. 
first car. Trainpipe pressure, 66.15 lbs. fiftieth car. 

Test No. 7. — Fifth trial: Engineer's valve open two seconds. 
Trainpipe pressure 69.30 first car. Trainpipe pressure 66.15 fiftieth 
car. 

The first car developed a pressure of 60.90 lbs., in 2.7 seconds and 
the fiftieth car apphed in 4.2 seconds from the movement of the 
engineer's valve, and reached a pressure of 57.75 lbs. in 7 seconds. 

Westinghouse Train. 

Test No. 7. — First trial : Trainpipe 68.30 lbs., first car. Train- 
pipe 67.20 lbs., fiftieth car. 

In o. 2 seconds after movement of engineer' s valve, first car applied 
and in I.I seconds reached a maximum pressure of 57.80 lbs. The 
fiftieth car commenced to apply in 2.6 seconds and reached a maximum 
pressure of 55.55 lbs., in 3.6 seconds. Brakes all on, and all released^ 

Test No. 7. — Second trial: Trainpipe 68.25 lbs., first car. 
Trainpipe 67.20 lbs., fiftieth car. 

In 0.2 seconds from movement of engineer's valve first car com- 
menced to apply and in i . i seconds reached a maximum pressure of 




Plate XII 
New York Brake. Test No. ( 




Plate XIII 
Westiuehouse Brake. Test No. 6. (Second Trial.) 



^"^^^^^ Air Brake Tests 



THE KARNER 
TESTS 



57.75 lbs.; fiftieth car commenced to ap- 
ply in 2. 7 seconds and reached a maximum 
pressure of 55.65 lbs., in 3.6 seconds. 

Test No. 7. — Third trial : A duphcate of trial No. 2 except the 
fiftieth car was 3.65 seconds in reaching 55.65 lbs. 

Test No. 8. — Special and Optional. 

Same as No. 7, except that the fifth to the tenth car inclusive was 
cut out. The New York Brake Co. did not choose to make this trial. 

In practical operations it is often quite as important to know what 
can not be done as it is to know what can be done. 

The Westinghouse Co. made the trial. The handle of the engineer's 
valve was held in the emergency notch i second, as usual. In four 
trials the emergency action beyond the cut out cars did not take place, 
then the forward rush of air with its stored energy would release the 
brakes. 

Test No. 9. — Graduation Tests. 

A reduction of 8 lbs. in trainpipe pressure was made, then at i 
minute intervals, further reductions of 4 to 6 lbs. were made until res- 
ervoirs and cylinders were equalized. Repeated twice. 

New York Train, 

Test No. 9.- — First trial : Trainpipe pressure reduced to 8 lbs. 
Pressure in trainpipe, first car, 69.30 lbs. Pressure in trainpipe, 
fiftieth car, 67.20 lbs. 

First car applied to in 0.9 of a second after movement of engineer's 
valve, and the fiftieth car in 9 seconds. In 20 seconds the pressure in 
the first car, 23.1 lbs.; fiftieth car, 15.75 lbs. 

In I minute pressure, in first car, 18.90 lbs.; fiftieth car, 10.50 lbs. 

Second application : 

One minute, trainpipe pressure, 57.75 lbs. 

In 10 seconds, pressure in first car, 40.95 lbs.; fiftieth car, 21.00 
lbs. In I minute, pressure in first car, 34.65 lbs.; fiftieth car, 13.65 
lbs. 



THE KARNER 
TESTS 



Air Brake Tests ^^^^^^^ 



It was noticed that the effect of the 
second application was felt in the fiftieth 
car in 4 to 5 seconds, about one-half of 
the time of the first application. This seemed to be the rule with both 
brakes. 

Several applications were made at minute intervals, the seventh not 
affecting the cylinders in either car. 

Eleven cars were reported as not applying beyond the leakage groove. 

The second trial of Test No. 9 was similar to the first, until the 

third application, which applied the brakes in full, as the fourth and 

fifth applications did not increase the pressure in either the first or 

fiftieth cars. 

Six cars were reported as not applying beyond the leakage groove. 

Westinghouse Train. 

Trainpipe pressure, first car, 68.25 lbs.; fiftieth car, 67.20 lbs. 

In 0.5 of a second brakes applied in first car, and in 6,j in the 
fiftieth car. In 10 seconds, first car, 8.40 lbs., and in the fiftieth car, 
4.20 lbs. 

At the minute, first car, 8.40 lbs.; fiftieth car, 7.35 lbs. 

Ten seconds after the second application, first car, 26.25 lbs.; 
fiftieth car, 15.75 lbs. 

Five applications were made in this test. 

Test No. 9. — Second trial : In 0.6 of a second brakes applied in 
first car, and in 6.9 seconds on the fiftieth car. This trial was similar to 
the others, except that seven appHcations were made. All brakes 
applied in both trials. 

Test No. 10. — Service Application. 

Fifteen pounds to be admitted into cylinders, pressure noted then at 
the 5th, loth, and 15th minutes. 

New York Train. 

Test No. 10. — The first car applied in 0.7 of a second, and the 
fiftieth car in 9 seconds. 

At 50 seconds, first car, 52.50 lbs.; fiftieth car, 38.85 lbs. 



^^^^^^^ Air Brake Tests 



THE KARNER 
TESTS 



At 5 minutes, first car, 47.25 lbs.; 
fiftieth car, 5.25 lbs. 

At 10 minutes, first car, 40.95 lbs.; 
fiftieth car, 2.10 lbs. 

At 15 minutes, first car, 37.80 lbs.; fiftieth car, 2.10 lbs. 

After the first 5 minutes 6 cars had released. 

After 10 minutes 2 more were also off; all the others remained on 

15 minutes. 

Westinghouse Train. 

Trainpipe pressure, first car, 68.25 ^^^* J fiftieth car, 67.20 lbs. 

Brakes applied in first car in 0.9 seconds, and in the fiftieth car in 
6y^ seconds. 

In 40 seconds, pressure was in first car, 31.50 lbs.; fiftieth car, 
26.25 ^^s- 

In 5 minutes, pressure in first car, 5.25 lbs.; fiftieth car, 4.20 lbs. 

At 10 and 15 minutes the readings were down to zero in both cars. 
The readings were affected by the indicators and their connections. 
All of the cars appHed. — 

One car released at the end of 5 minutes, and in 1 1 minutes another 
car, and a third car in 1 2 minutes ; all the others remained on i 5 minutes. 

Test No. i i. 
Same as No. 10, except all the air was exhausted from trainpipe by 

emergency apphcation. 

New York Train. 

All brakes applied, and none leaked off fully at the end of i 5 minutes. 

Westinghouse Train. 
Mr. Wm. Buchanan, Superintendent Motive Power and Rolling 
Stock, requested that the time be extended in this test to 30 minutes, 
which was done, the New York train being subsequently tested the 
same length of time on another track. All Westinghouse brakes applied 
and remained on the 30 minutes, except one car which leaked off. 

Test No. 12. — Release Test. 
Boiler pressure, 160 lbs.: With 70 lbs. in the trainpipe, all the 
air was discharged by an emergency application. A pressure of 90 



THE KARNER 
TESTS 



Air Brake Tests ^"^^ '^° 

lbs. was then maintained against a dia- 
phragm y^ in. thick, perforated with 
-g^^-in. hole, and a record taken of all 
brakes, which released in 30 minutes. 

New York Train. 

Pressure 22 lbs. in 5 minutes. One car released in 2 minutes; 
three in 3 minutes ; four in 4 minutes ; three in 5 minutes — or eleven 
in 5 minutes or under. r 

At 10 minutes the pressure was 40 lbs. Six cars released in 6 
minutes ; ten in 8 minutes ; seven in 10 minutes. 

At 1 5 minutes the pressure in trainpipe was 47 lbs. Eleven cars 

released in 14 minutes. At the end of 30 minutes one car did not 

release. 

Westinghouse Train. 

Trainpipe pressure at the end of 5 minutes, 10.50 lbs.; 10 minutes, 
38.85 lbs.; 15 minutes, 53.55 lbs.; 20 minutes, 59.85 lbs.; 30 
minutes, 70.36 lbs. 

One car released in 5 minutes ; two in 6 minutes ; six in i o min- 
utes ; seven in 1 1 minutes ; nine in 1 2 minutes ; ten in 1 5 minutes ; 
twelve in 18 minutes ; three did not release at the end of 30 minutes. 

Test No. 13. 

Test to determine the sensitiveness of the emergency valve. 

The first and fiftieth car was cut from the train and connected 
together by hose ; 70 lbs. pressure was then maintained and discharged 
into the trainpipe through a diaphragm perforated with 3^2""^^* ^^^^' 
Each car to be tested singly, if desired. 

New York Train. 
Trainpipe, 71.40 lbs. First trial, emergency action occurred in 
both cars. Second trial, emergency action did not occur. Third trial, 
emergency action did not occur. Fourth trial, first car only, emer- 
gency action occurred. Fifth trial, emergency action occurred. Sixth, 
seventh and eighth trials, with the fiftieth car, emergency action did 
not occur. 



1 



^''^''^' Air Brake Tests 



THE KARNER 
TESTS 



Westinghouse Train. 
Trainpipe 7 2 . 4 5 lbs . First and fiftieth 
cars, emergency action did not occur. 
Second trial, emergency action did not occur. Third trial, emergency 
action did not occur. Fourth trial, first car only, emergency action 
occurred. Fifth and sixth trials, fiftieth car only, emergency action did 
not occur. 

Test No. 14. 

Test to determine time of charging one auxiliary reservoir. Cars 
arranged as in test No. 13, only brakes cut out and reservoir pressure 
bled off. Ninety lbs. pressure secured in main air reservoir and train- 
pipe ; pump shut off and time of charging reservoir to 70 lbs. noted. 

New York Train. 
First car charged in 72 seconds. Fiftieth car charged in 60 seconds. 

Westinghouse Train. 
First car charged in 70 seconds. Fiftieth car charged in 80 seconds. 
Second Trial. — First car charged in 69 seconds. Fiftieth car 
charged in 87 seconds. 

Running Trials. 

The Westinghouse train was assigned to track No. 4 and the New 
York train to track No. 3. The governors for the air pressure were 
set in the morning of the 9th. The brakes on each tender were also 
adjusted after the locomotives were attached to the trains. 

Determination of Speed of the Running Trains. 

It was impracticable for the Dynagraph car to be on either train, so 
electrical trips were erected on each track 88 feet apart, or -J^ of a 
mile. 

Both tracks were supplied with these trips ; one being located 8 8 
feet above the signal banner ; another at the banner to give the initial 
speed, and the others at proper intervals extending several hundred feet 
below the signal banner. These were in circuit with the electro-mag- 
netic pens of the recording mechanism of the Dynagraph car which 
stood upon a side track near where the stops would occur ; then by 




Air Brake Tests ^''^'^^^ 

running the paper as the train passes, 
the interval of time in running over the 
spaces w^ould be recorded. 

The trips had a base-board 5 in. w^ide by 24 in. long, in the center 
of w^hich w^as secured a block carrying a tripping paw^l, w^hich held in 
position a gravity lever, its fulcrum being near its lower end. Back of 
this gravity lever w^as a spring and contact point for a circuit closer ; 
the circuit w^as open v^hen the gravity lever vs^as up, but v^hen released 
and falling, closed the circuit about 2-^^ of a second ; then the spring 
opened the circuit during the last part of the fall to leave the circuit free 
to be closed and opened by the next trip, and so on. 

The forw^ard truck w^heel operated the tripping pawl. These trips 
were very carefully adjusted as to the length of contact and the exact 
angle at which they would close the circuit during their fall. 

The records obtained from these trips after the air was applied only 
refer to the speed of the locomotives and not to that of the entire trains 
the front, middle, and rear portions having different velocities for a few 
seconds during retardation. 

A banner directly over the tripping blocks in tracks Nos. 3 and 4 
v^as the signal for the engineers to shut off steam when the cabs were 
under it ; the levers being tripped at the same point, applied the air 
with a precision and quickness impossible by the engineer's valve. 

To give the locomotives distance to work up the speed desired, the 
trains w^ere backed two miles for thirty miles per hour and under, and 
for higher speeds three miles, and then ran side by side on parallel 
tracks to the signal banner at as near the same speed as possible ; with 
the exception of No. 4 run, both engines reached the banner nearly 
at the same instant. The trains were run with great skill ; much 
better than it was thought possible to handle such long trains, and the 
engineers are entitled to great credit for their work. 

The tabulations of the observed data of the running trials are so 
explicit as to require but little further explanation, and this will gen- 
erally be given with the energy diagrams. The only calculations in 
the tabulations are those for the speeds, from the times given by the 
trips, which have been carefully revised, and, with the exception of trip 



^"^^^-^-^ Air Brake Tests 



THE KARNER 
TESTS 



No. 4, the initial speeds are closer 
approximations than are usually obtained. 

The time of stop only refers to the 
Westinghouse train, as the other could not be observed from the car ; 
when the train parted, the time is shorter than the time of the move- 
ment of the locomotive. 

The gauge readings of the observers have been corrected to the read- 
ings of the standard gauge. In the running trials, the readings of the 
gauges on the trainpipe could be correctly obtained, while those for the 
reservoirs and cylinders were more difficult to read correctly. In the 
^Nt comparative runs, except in No. 4, the train running the farthest 
had the highest trainpipe pressure, but the slower rate of development 
in the cylinders, though finally attaining a higher maximum pressure. 

The time of application per car and train were given in the standing 
tests in the tables of No. 6 tests, and the curves of development of 
pressure per cylinder by the indicator diagrams of the same tests. 

Energy Diagrams. 

From the observed speeds of the locomotive, for each train and trial, 
curves of their retardation were plotted by full lines for the observed 
spaces, then to the point of the stop by a broken line, the latter being 
only a general approximation. 

There was also added an approximate curve of broken lines or 
dashes to represent for the center of gravity of the train its total energy 
and rate of destruction. There should also be added a third curve to 
represent the energy of the rear unbraked cars ; for as they continue 
their speed they not only compress the draw-bar springs but push the 
front of the train and locomotive beyond the point where they would 
have stopped had their rate of retardation remained unchanged. This 
is shown in all the energy diagrams. 

In the slower trials it was about 3 seconds before the locomotive 
was affected, while in the higher speeds it was 4 or more seconds. 



Table XXX. — Running Trials No. i. Temperature 72° Fahr. 
Time 11.30 A. M. 





Westinghouse Train. 


New Yor 


K Train. 




Miles per 
hour. 


Time, 
seconds. 


Miles per 
hour. 


Time, 
Seconds. 


Initial speed 
First 88 fe 
Second 88 ' 
Third 88 ' 
Fourth 88 ' 


et . . . 




26.78 
25.32 
21.12 


2.24 
2.37 
2.84 


26.78 
25.86 
22.69 


2.24 
2.32 
2.64 


( 




( 












Length of stop 


270 


feet 


310 


feet 


Time of stop 


10.6 


seconds 






or J ^ i First car 

Shdeometer ■{ ^.r ■ ^, 

/ Fiftieth car . . . . 


.25 inch 
4 in 


.25 inch 
ches 


1.75 
26.50 


inches 
inches 




Charged. 


Applied. 


Charged. 


Applied. 


Air pressure ■< 


' First 
car 

Fiftieth 
car 


( Trainpipe 

< Reservoir 
( Cylinder 

[ Trainpipe 

< Reservoir 
f Cylinder 


68. 
68. 

00. 

68. 
68. 

00. 


00. 
56. 
56. 

23. 

55- 
55- 


71. 
71- 
00. 

71. 
71- 
00. 


26. 

59. 

58.50 

40. 

59- 
59- 



Table XXXI. — Running Trials No. 2. 
Time 12.00 M. 



Temperature 80° Fahr. 





Westinghouse Train. 


New Yok 


K Train. 




Miles per 
hour. 


Time, 
seconds. 


Miles per 
hour. 


Time, 
seconds. 


Initial speed 

First 88 feet .* . 

Second 88 " 


32.00 
31.17 
29.54 

19.44 


1.875 
1.925 

2.037 

2.17 

4.00 


32.00 

31-58 
29.70 
27.06 


1.875 
1.900 
2.020 


Third 88 "........ 


2.217 


Fourth 88 " 


1 76 feet 








Length of Stop 


373 


feet 


450 


feet 


Time of stop 


11.50 


seconds 




0,. , ( First car 

Shdeometer ■< T-r- 1 

/ Fiftieth car . . . . 


.25 inch 
.50 i 


.75 inch 
nches 


.5 inch 
31.00 


.75 inch 
inches 




Charged. 


Applied. 


Charged. 


Applied. 


^ First 
car 

Air pressure < 

Fiftieth 
car 


( Trainpipe 
-| Reservoir 
( Cylinder 

( Trainpipe 
- Reservoir 
( Cylinder 


68.5 
68. 

00. 

68. 
68. 
00. 


27. 
57. 

57. 

47- 
50- 
49. 


71. 
71- 
00. 

70.5 
70.5 
00. 


20. 
55- 
54- 

00. 
58. 
58. 



Note. — Broken brake-beam on tender 
car uncoupled. 



of engine on the New York train ; track No. 3 ; last 



Table XXXII. — Running Trials No. 3, 
Time 2.10 P. M. 



Temperature 80° Fahr, 



Westinghouse Train. 



Initial speed 

First 88 feet . . . . 
Second 88 " . . . . 
Third 88 " . . . . 
Fourth 88 *'.... 

Length of stop .... 

Time of stop 

ci-j . \ First car . 

Sudeometer ■{ ^.r- ^1 

' Fiftieth car 



Miles per 


Time, 


Miles per | 


Time, 


hour. 


seconds. 


hour. 


seconds. 


34.48 


1.74 


34.48 i 


1.74 


33-74 


1.778 


33-99 1 


1.762 


31.43 


1.906 


32.26 i 


1.860 


27.77 


2. 160 


28.82 


2.079 


22.89 


2.622 







New York Train. 



472'; train parted 34.8' be- 
tween fifth and sixtii cars ; 
broken knuckles. 



496'; train parted 38.3' be- 
tw'n twelfth and thirteenth 
cars ; broken knuckles. 



.5 inch 
.5 do 



.5 inch . I inch 
28.25 inches 



Charged. 



Air pressure 



First 
car 



i Trainpipe 
-\ Reservoir 
( Cylinder 



Fiftieth ( ^"'•^'"P'P^ 
-< Reservoir 

f Cvlinder 



64.50 
63.50 
00. 

65. 
64.5 

00. 



Applied. 
00. 
54. 
54. 

47- 
47. 

45- 



Charged. 



Applied. 



69. 


20. 


69. 


53. 


00. 


53- 


70. 


41. 


69. 


58. 


00. 


58. 



Table XXXIII. — Running Trials No. 4. 
Time 3.20 P. M. 



Temperature 78° Fahr. 





Westinghouse Train. 


New York Train. 




Miles per 
hour. 


Time, 
seconds. 


Miles per 
hour. 


Time, 
seconds. 


Initial speed 

First 88 feet 

Second 88 '• 

Third 88 '■' 

Fourth 88 '' 


30.30 
30.00 
25.72 
20.41 


1.980 
2.00 
2.333 
2.939 


31.88 

31-39 
28.29 

25.07 


1.882 
1. 911 
2. 121 
2.393 


Length of stop 


325 feet. 

Parted about one car 

length. 


417 feet. 

Parted about one car 

length. 


Time of stop 


1 1 seconds 




„,. , { First car 

Sudeometer i ^^.r- 1 

/ Fiftieth car . . . . 


00. 
6. inches 


f inch 
26.5 inches 




Charged. 


Applied. 


Charged. 


Applied. 


Air pressure -< 


r First (Trainpipe 
•< Reservoir 
^^"^ ( Cylinder 

Fiftieth \ I'^^^P'r 
•\ Reservoir 

^^^"^ (Cylinder 


72. 

71. 
00. 

72. 
71- 
00. 


00. 
60. 
59" 

28. 
56. 
56. 


65. 

65. 
00. 

63. 
63. 

00. 


00. 
53- 

47. 

23. 

53. 

53- 



Note. — This was ordered for a speed of 40 miles per hour, but the driver brakes were stuck 
on the New York engine and the other engine was slowed down to her speed. 



Table XXXIV. — Running Trials No. 5. Temperature 77° Fahr. 







Westinghouse Train. 


New Yor 


K Train. 




Miles per 
hour. 


Time, 
seconds. 


Miles per 
hour. 


Time, 
seconds. 


Initial speed 

First 88 feet 

Second 88 " 

Third 88 " 

Fourth 88 '' 


28.39 
28.39 
28.39 

28.18 
26.47 


2. 113 
2.II3 
2. 113 
2.I3I 

2.267 


28.39 
28.39 
28.39 
27.94 


2. 113 
2.II3 
2. 113 

2.147 


Length of stop 


844 feet 


957.5 feet 


Time of stop 






\ First car 

Slideometer - ^.^ . , 

} Fiftieth car . . . . 


00. 
3. inches 


f inch 
1.25 inches 




Charged. 


Applied. 


Charged. 


Applied, 


Air pressure < 


r First ^Trainpipe 
< Reservoir 
'^^'' ( Cylinder 

Fiftieth ( I'^^^^P^P^ 
-< Reservoir 

^^^^ ( Cylinder 


68. 
68. 

00. 

68. 
68. 

00. 


46. 
46. 

45- 

36. 

44- 
33- 


70.5 
70.5 
00. 

67. 

67. 
00. 


SO- 
45- 

SO. 
SO. 
50. 



Note. — Service stop by air passing through a diaphragm perforated with a sVii^. hole. 

Table XXXV. — Running Trials Nos. 6 and 7. Temperature 70° Fahr. 
Time of No. 6, 5.38 P. M. ; No. 7, 5.45 P. M. 



Initial speed 

First 88 feet 

Second 88 " 

Third 88 " 

Fourth 88 " 

Length of stop 

Time of stop 

„.. , ( First car . . 

Slideometer -^ ^-r- ^u 

/ Fiftieth car . 



Test No. 6. Test No. 7. 

Mixed Forty-Five Cars. Mixed Fifty-Five Cars. 



Miles per 
hour. 



27.75 
27.44 
25.62 
19.84 



Time, 
seconds. 



2. 162 
2.186 

2.342 
3.024 



Miles per 
hour. 



30.00 
29.27 

2S-63 
20.83 



Time, 
seconds. 



2.00 
2.05 

2.341 
2.881 



325 feet. 

Parted it two places, about 

forty-five feet. 



344 feet. 
Parted in three places. 



10. 3 seconds 



00. 
10.25 ii^ches 



J and J inch 
23.5 inches 



Charged. 



Air pressure 



' First 
car 

j Fiftieth 
[^ car 



i Trainpipe 
-I Reservoir 
( Cylinder 

Trainpipe 
Reservoir 
Cylinder 



65. 
64. 

00. 

63. 
64. 

00. 



Applied. 



Charged. 



00. 

53- 
S3. 



SO. 



72. 
72. 
00. 

70. 
70. 
00. 



Applied. 



22.5 
58. 

S4. 

^s. 
ss- 



Note. — Train of trial No. 6, composed of twenty-five cars Westin 
cars New York brakes, mixed. Train of trial No. 7, composed of thi 
and twenty-five cars Westinghouse brakes, mixed. 



ghouse brakes and twenty 
rty cars New York brakes 











^•^...^^.,,^___^ paddojs Qi^JX 


e changes in ten- 
drawbar of the 
the trains, after 
jplying the air. 


^- 


Fig. 103 

Diagram illustrating th 
sion and compression or 
locomotives in stopping 
shutting off steam and a] 

"X 




'^ 


V 


/ 


\ 

1 


jgo ^nqs ui^a^g 


i 






uuisuojL, 




noisso.idmo^ 



THE KARNER 
TESTS 



Air Brake Tests ^^^^^^^ 



In the energy diagrams showing the 
curves of both trains, in trial No. i, 
diagram in Fig. loi, the speed of the 
locomotives was retarded in the first 88 ft., and had the same rate con- 
tinued would have stopped many feet short of the actual stop. In the 
second 88 ft. the locomotives were pushed forward by the energy of 
the rear cars ; while in the next 88 ft. the locomotives were again 
being retarded by the train. 

The general changes in tension and compression on the draw-bar of 
the locomotives at Karner are illustrated by a special diagram. Fig. 

I02. 

Trial No. 2, diagram in Fig. 103, at 32 miles per hour, with over 
59,000,000 foot lbs. of energy to destroy, is one of the most impor- 
tant diagrams of the series. The vast amount of energy was not only 
quickly destroyed, but without the slightest injury to the trains. 

The speed of the locomotive for the Westinghouse train was obtained 
to within a few feet of the stop and shows closely its curve or retard- 
ation ; first, the rapid retardation ; second, the checking of its rate ; 
third, rapid retardation. 

The obtained speed of the locomotive of the New York train is one 1 1 
space short of the Westinghouse train, yet its curve of retardation is 
closely shown. 

Trial No. 3, diagram in Fig. 104, a speed of 34.48 miles per hour, 
shows a total energy of 68,598,814 foot lbs. for each train, capable 
of doing work equivalent to raising the entire train over 40 ft. above 
the track. Anyone will understand that if a train was allowed to fall 
40 ft., the locomotive and every car would be a wreck. The same 
amount of energy was destroyed by the brakes in a harmless way in 
about one-fourth of the train's length, a broken knuckle on each train 
being the only thing to indicate that any great amount of work had 
been done. The speed for the distance run was a greater tax upon the 
locomotives than in the preceding trials, the steam and air pressure 
falling slightly. Both trains parted just before the stop, an allowance 
being made in plotting each curve as shown on the diagrams. 

Trial No. 4, diagram in Fig. 105, was ordered for a speed of 40 



,4 

i 


.d 

S 




20 
m. per hr. 




o 




1 
Fig. 104 T^o. 3 Running Test. 

Energy Diagrams. 
Emergency Stop. 


i 

o 
fc. 

1 


t 

1 

o 

B 

i 
1 




/ 


/ /■ 


^1: 


y''\ 


i 


/ 
/ 

/ /-/ 
//■/ / 


<♦ X / 

/ // / 

f / 


1 '^ 

1 '^ 




CO i 

^ i 
-2 1 


^ ! 

CO 1 

3 [ 




/ 
/ 
/ ; 

/ / 

/ / 


* / / / 
f / / / 








3 1 


I i 

ti 

CM «. 

5 El 
■^ • 


GO 
00 






1 / / / 
f ' / / 
1 .' / / 

if / / 

J/ / / 

1/ o / / 

// ^/ / 

HI 

II ^1 / 

i' ' 






ii J 




'^1 

o 1 

r" 1 


o 1 




1 1 
1 1 1 
1 II 

' // 
' // 
. ' // 

rd \ II 
&' // 

ccljl 


•sqi 000 'b 


eg 'I 'sniBJx JO ^qs 


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•¥f6S'T80'e ■ 

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a: JO -a 1 




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a 




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si 

a 




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X 

cc 






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X 


Fig. J 06 No.5 1liii] 

Energy Diag 
Service St 

Wostiiiffhonsfi _ 

"ATnw Vnrlr Tvoin 


o 

o 


y 












X 




1 




1 

! 








i 










1 
1 

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X 



THE KARNER 
TESTS 



Air Brake Tests ^"^'^^^ 



miles per hour ; the engineers, as quick as 
the stop was made, to release and see which 
could back up their train first. 

The engines passed by each other three or four times in trying to 
equalize their speeds. The distance was too short to do so and have 
the entire length of the train all in uniform motion, so the initial speeds 
given by the locomotives did not give the speeds of the train as closely 
as in the other trials. Both trains parted, and someone instantly closing 
the trainpipe cocks on the front of the trains, the engineers released at 
once and backed against the rear portions before the partings could be 
measured. Both trains had to be repaired before they could be coupled. 

Trial No. 5, diagram in Fig. 106, was in the nature of a service 
stop, the air being discharged through a diaphragm perforated with 
a -^-in. hole placed in the tripping device pipe for each locomotive. 
The air was applied faster than through the engineer's valve ; however, 
the train was not sensibly affected until the third space was reached ; 
the 46,506,420 ft. lbs. of energy to be destroyed required 32 seconds, 
and the long distances run in which to do it. 

Trial No. 6, diagram in Fig. 107. The cars of the two trains 
were switched and made up into mixed trains. Forty-five cars were 
distributed, as follows : 5 Westinghouse, i o New York, i o West- 
inghouse, 10 New York, and 10 Westinghouse in the rear. The 
speed was 27.75 iriiles per hour; 40,539,744 ft. lbs. of energy to be 
destroyed. The curve of retardation of the locomotive is sinuous, the 
train parting in two places. 

Trial No. 7, diagram in Fig. 108, 55 cars were distributed, as fol- 
lows : 5 New York, 5 Westinghouse, 5 New York, i o Westinghouse, 
10 New York, 10 Westinghouse, and 10 New York on the rear of 
the train. The speed was ordered for 30 miles per hour, and run ex- 
actly, having 56,480,436 ft. lbs. of energy to be destroyed. Train 
broke in two. 

Shocks occurred to both of these trains. The energy diagrams for 
the same and different trials show, irrespective of the kind of brakes, 
the value and importance of time in the application. Comparing No. 
I Trial with No. 2 and No. 3 of the Westinghouse train, plotting 









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§8 


Eig. 1 08 IVo.y Running Test. 
Energy Diagrams. 
Emergency Stop. 

Full lines from observed speeds. 

Mixed.Train, 

N.Y. -W. N.Y. W. N.Y. ^y. N.Y 

10 10 10 10 15 5 5 






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i 



THE KARNER 
TESTS 



Air Brake Tests ^''^''^^ 



each back from the stopping points (Dia- 
gram in Fig. 109), No. i, with a speed 
of 26.78 miles per hour, stopped in 270 
ft., less than ^ of the train length; the energy destroyed being 
41,381,280 ft. lbs. The train in Trial No. 2, for the same distance 
still to run, had a speed of 30.5 miles per hour, the air having been 
applied about 2 seconds, and destroyed over 52,000,000 ft. lbs. of 
energy. No. 2 reduced to the same speed as No. i started v^ith, 
when the air had been on about 41^ seconds ; No. 2, therefore, 
destroyed as much energy in the last 174 ft. as No. i did in 270 ft. 

The comparison between Nos. i and 3 (Diagram in Fig. no) is 
still more striking ; when No. 3 had the same distance to run as No. i , 
there were 59,000,000 ft. lbs. of energy still to be destroyed, and in 
the last 166 ft. No. 3 destroyed as much energy as No. i did in 270 ft. 

The increase of the coefficient of friction as the speed decreased 
helped to more rapidly destroy the energy, but it was largely due to the 
more complete application of the air per car and train. From this the 
importance of applying the air as quickly as possible per cylinder and 
train is clearly indicated. 

A comparison of Trials Nos. 1,2, and 3 of the New York train, 
in Figs. 109 and 1 10, shows the same general results, except that the 
distances run were longer to destroy a similar amount of energy. 

Shocks. 

As shown by the energy diagrams, some shocks were likely to be 
experienced in destroying the vast amount of energy in the moving 
trains, and, further, the magnitude of the shocks, as shown by the tabula- 
tions, was affected by the time required for the brakes to become effec- 
tive from the first to the fiftieth car. The shocks of greatest magnitude 
did not occur when the brakes were first applied, nor at the final stop, 
but, for the trains tested, between 4 and 6 seconds after the air was 
applied in the emergency stops. Although not measured, yet it was 
longer in the service stop, as shown by the diagrams. 

Although incidental to these trials, the time of appHcation of air 
from the first to the fiftieth car is here given, and the occurrence of 









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THK KARNFR 



Jir Brake Tests '■"'-'''* 



shocks on the fittieth car on the ^^'est- 
inghouse train as observed with special 
electrical apparatus. 

Trial No. i, inter>^al after application tirst car to application fiftieth 
car, 2.45 seconds. 

Trial No. I , inter\*al after application first cir to shock fiftieth car, 
5,70 seconds. 

Trial No. 2, inter\^al after applicadon first car to application fiftieth 
our, 2.6S sec^Mids. 

Trial No. 2, inten'al after application first car to shock fiftieth car, 
5,73 seconds. 

Trial No. 4, inter\'al after application first car to application fiftieth 
car, 2.41 seconds. 

Trial No. 4, inter\^al after application first car to shock fiftieth car, 
4.94 seconds. 

Note. — Trial No. 3 was lost. 



Table XXXVI. 

Compansons of ** G^ihons Table No. X/' by the distance run in feet after hve 
second intenrals showmg redtKtkms of coefficient of friction. 



Speed aad 

CoefBcie-nt. 


Fire Seconds. 


Ten Seconds. 


Fifteen 

! Seconds. 


Twenty 

Seconds. 


;c miles 
.1S2 

ReducDon 


14- feft 
.152 


.civ; 


441 feet 
.118 
.015 


5SS feet 

' .099 

.019 


2- miles 
.1-1 

Reduction 


igS feet 

130 

.041 


396 feet 
.119 

.CII 


^94 feet 
.oSi 
.038 


-92 feet 
.072 
.009 


37nifles 

.15a 
Redaction 


272 ieet 
.096 
.056 


544 feet 
.083 
.013 


S16 feet 
.069 
.014 




47 mUcs 

.13a 
RcdiKtkMi 


345 feet 

.oSo 
,052 


691 feet 

.0-0 
.010 






60 nuks 

.072 
Reduction 


440 feet 
.065 
.009 


S80 feet 
.058 

.005 







^^^^^^^ Air Brake Tests 



THE KARNER 
TESTS 



No instrument was prepared to measure 
the time of the shocks in the New York 
train, but the observer for the fiftieth car 
said it occurred about as soon as they could get braced for it after 
feeling the brakes apply. 

These trials showed that, within the practical limits of applying air 
to the train, the shocks were rendered so small as to be of no moment. 

The Coefficient of Friction. 

The trials at Karner indicated that the distance run after the shoes 
were applied was quite as important a factor as time in reducing the 
coefficient of dynamic friction. 

Table XXXVII. 



Trial, 



Westinghouse Train. 



New York Train. 





26.78 


miles to 


25.1 


.057 


26.78 


miles to 


26.30 


.049 




25.1 


do. 


20.1 


.148 


26.30 


do. 


24.40 


.062 


No. I 


20.1 


do. 


5.« 


.249 


24.40 


do. 


19.30 


.148 




5-« 


do. 


0.0 


.322 


19.30 

7.20 


do. 
do. 


7.20 
0.00 


.206 
.313 




32.00 


miles to 


30.6 


.057 


32.00 


miles to 


31.00 


.039 




30.0 


do. 


27.8 


.107 


31.00 


do. 


29.00 


.080 


No 2 


27.8 


do. 


22.5 


.186 


29.00 


do. 


25.50 


.124 




22.5 


do. 


10.8 


.255 


25.50 


do. 


19.60 


•175 




10.8 


do. 


0.0 


.321 


19.60 

7.50 


do. 
do. 


7.50 
0.0 


.215 
.324 




34.48 


miles to 


33.6 


.039 


34.48 


miles to 


33.6c 


•^^39 




33.6 


do. 


31.6 


.084 


33.60 


do. 


31.70 


.081 




31.6 


do. 


27.4 


.164 


31.70 


do. 


28.30 


.134 


No. 3 


27.4 


do. 


20.8 


.201 


28.30 


do. 


22.40 


.192 




20.8 


do. 


5-0 


.267 


22.40 


do. 


12.20 


.230 




5-0 


do. 


0.0 


.320 


12.20 
5.00 


do. 
do. 


5.00 
0.00 


.276 

.320 



As the coefficient of static friction appears to be practically constant 
at different speeds, the constant brake-shoe pressure in the trials caused 
the coefficient of dynamic friction to be a very small percentage of the 
static coefficient at higher speeds. 

The approximate percentages of the coefficient of static friction 



THE KARNER 

TESTS 



Air Brake Tests ^^^^^^^ 



realized by the coefficient of dynamic 
friction at Karner trials Nos. i, 2, and 
3 for each train are given below. 

Approximate curves from some of the above figures w^ere plotted 
upon the diagrams. Figs. 109 and 1 10, and indicate some of the many 
complicated phases of the brake problem. The vertical height of the 
curve represents the percentage of the static coefficient that is obtained 
by the dynamic coefficient at the speed show^n by the retardation curves 
above, and at the proportion of stop show^n by the horizontal scale in 
feet. 

With the M. C. B. standard of 70 per cent, of the v^eight of the 
empty freight cars as pressure on the brake shoes, even after the air was 
fully applied, nowhere near the full value of the coefficient of static 
friction was realized until near the stop. 

The coefficient of static friction with a dry rail has a safe working 
value of .290 for the weight of the empty cars used in these trials, and 
on the energy diagrams were approximately represented by the line 
marked 30 miles per hour. The space below that line to the curve 
obtained shows the possibilities of practice — the length of stop being 
correspondingly reduced. For a ^^ moist, slimy" rail the coefficient 
reduces to about .200 ; the line marked 25 miles per hour approximately 
represents the working limit of static friction. 

Conclusions. 

Referring to table No. IX. ( The Galton Trials), giving the approx- 
imate coefficients of dynamic friction at different speeds, it will be 
readily seen that to utilize more nearly the full value of the coefficient 
of static friction for the fastest passenger trains and loaded freight trains, 
the brake shoe pressure must be largely increased, at high speeds, re- 
ducing as the speed decreases. 

The curves indicated that at 60 miles per hour the brake shoe pres- 
sure could be doubled, reducing to about i ^^ times at 40 miles and 
to the ordinary for the stop. 

For heavy or high speed trains, the energy to be destroyed is so great 
that the brake mechanism must not only be efficient but ample to bring 



^""^''^^ Air Brake Tests 



THE KARNER 
TESTS 



the train under control in emergencies 
from the distant to the home signal. 

The trials at Karner also showed the 
increase in coefficient of friction due to time of application. This 
feature, and the rear unbraked cars running up against the front braked 
ones, seem to have modified the mean curves of realized static friction, 
so that the curves are not continuous but have two branches, the least 
modification from a continuous curve being in the shortest stops. This 
will be noticed in the friction diagrams. Figs. 109 and 1 10. 

The locomotive had the air applied the full time, the next car a fi*ac- 
tion of a second shorter, and so on for each car, the time reducing to 
about 8.5 seconds on the fiftieth car. The curve of fi-iction for the 
fi-ont and rear cars of each train would be quite similar to those shown 
in the diagram in Fig. 109, the curve for the front cars corresponding 
to the curve for No. 2 trial, and for the rear cars to the curve of 
No. I, the quickness and intensity of action increasing from the fi^ont 
to the rear of the train. The strains thus induced or grouped had to 
be equalized by the draft rigging, which broke in each train for all 
emergency stops after the second trials. 

Examinations under the microscope of the surface of a few of the 
worn cast-iron shoes showed in general abrasion at all speeds, but they 
indicated at high speeds a wearing away of the metal by flowing off 
and reducing to thin flakes, some portions attaching and filling interstices 
made in preceding stops, others detaching in small particles ; while at 
slow speeds, especially near the stop, the metal seemed to be torn out 
in larger particles, scoring deeper and producing an effect similar to that 
of sanding the shoe, though in a less degree. 

The M. C. B. Association recommendations of tests for standard air 
brakes did not state whether the time interval of 3 ^ seconds fi-om the 
first to the fiftieth car, and 55 lbs. pressure in the latter, should be 
measured on a 50-car train, either standing, running, or on a rack. 
The time obtained fi-om rack tests, 6-in. piston travel, indicated .3 of 
a second less than obtained in the standing tests. 

In the time of applying the air to the entire train, the tests at 
Karner indicated the great advance made in braking over the experi- 



THE KARNER 
TESTS 



Air Brake Tests ^""^'^74 



ments at Burlington in 1886 and 1887. 
In 1886, on a 50-car train, 13 seconds 
was the time reported for the air to apply- 
on only the twenty-fifth car ; and in 1887, with improved valves, 41^ 
seconds. At Karner, Nos. i and 2 trials, the air was applied and the 
train stopped in 1 1 and 1 2 seconds, respectively ; the air being fully on 
one train in less than 4 seconds. 



)0( 



THE SANG HOLLOW TESTS. 

In the summer of 1900 a very extensive series of tests were made 
by the Pennsylvania Railroad Company on their West Penn Sang 
Hollow extension, just east of Bolivia, Pa. 

The principal question that was to be decided by these tests was the 
advisability of operating air brake equipments of the Westinghouse Air 
Brake Company and of the New York Air Brake Company in the 
same train. It is a well-known fact that whereas the construction of 
the triple valves of these two makes of brakes very closely resemble each 
other in principle, their action in emergency application is quite different, 
due to difference in construction and operation, so that in making certain 
kinds of stops the behavior of the brake for this reason is different, and 
the question was brought up whether the two could be operated in the 
same train with safety and reliabihty. 

The Pennsylvania Railroad determined to settle this question for 
themselves, and obtained from both of the above-mentioned companies 
fifty of their then standard freight triple valves and made a thorough 
series of tests upon a 50-car freight train with, first, all of the cars 
light, and, second, with 48 out of the 50 cars loaded as far as 
possible with just 80,000 lbs. of pig iron. As the loaded train tests 
may be considered of more importance from a practical point of view, 
the results of these alone are given herewith and the conclusions based 
upon them. 

The portion of track selected on the Sang Hollow division was 
practically level and free from such curves as would impose disturbing 
elements in the results of the test. It was carefully divided off into 
certain equal distances, stakes driven beside the track at each point, 
in order to determine the speed of the train when the brake was 
applied, and the distance run during the stop. These stakes were 
placed 100 feet apart and were so distributed that 88 stakes were 
passed before reaching the tripping point for automatically setting the 
brake, and were carried beyond this point for 3,500 feet. The usual 
electrical mechanisms for measuring speed and time were employed, and 
both standing and running tests were made to determine the rapidity and 



THE 

SANG HOLLOW 

TESTS 



Air Brake Tests ^"^'^^^ 



power of application quite similarly to 
those just described in the Karner tests. 
In the present trials the number of dif- 
ferent tests were much larger than in the Karner trials and covered a 
wider range of variations in make-up of train. No official report of 
these tests was ever published and consequently the description herewith 
gives simply the results in tabulated form, without entering into any 
details of each test. 

As mentioned above, 48 of the 50 cars were loaded ; the first and 
fiftieth were light and used for the purpose of making records of the 
tests. Gauges were connected to the trainpipe, and to the reservoir, 
and also to the cylinder in the first, twenty-fifth, and fiftieth cars ; in 
the latter was also placed a sHdeometer. 

The runs were divided into three series ; first, with the New York 
triple valves ; second, with various mixtures in the same train ; third, 
with the train equipped throughout with the Westinghouse triple valves. 
Each of these series were to be run at two speeds, viz. : 20 and 
35 miles per hour. The trainpipe pressure throughout was 70 lbs. 
The gauges used in the engines and on the reservoir and trainpipe of 
the first car were tested every day and a correct table kept covering 
the day's run. Before starting each day, the trainpipe was tested to 
determine leakage, and the piston travel throughout the train was noted. 
This latter was adjusted to be not less than 51^ inches nor more 
than 6^ inches. 

Stops were made with the following different applications of brakes : 
1st, emergency; 2d, full service; 3d, 6 lb. service reduction; 4th, 
emergency following 6 lb. service reduction. The emergency pro- 
ceded by a 6 lb. service application was arranged for the preliminary 
service reduction to occur at the following distances in feet before pass- 
ing the trip to apply the emergency : 100, 150, 200, 250, 300, and 
900. 

After the above series were completed, a supplementary series was 
added using 90 lbs. trainpipe pressure. This series was run with 
emergency application, full service application and emergency preceded 
by 6 lb. service reduction at 300 ft. The emergency and full service 



TABLE No. XXXVIII. 











2i 

3 


3 

X 


Distance. 






3 


3 


Arrangement 


Character 


0^ 


a. 








X 


of 


of 


s 


tJ 


V 


V 






&, 




V 


a. 


ex, 


Brakes. 


Application. 


'S, 


■;§ 


m 


S 


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c 




rt 










■«5 


i 


1 


S 


'i 






h 


0. 

CO 




< 


< 


Westinghouse . . 


Emergency 


70 


20.9 


391 


360 




do. 






do. 


70 


21. 1 


388 


351 




New York . . 






do. 


70 


21.4 


451 


397 




do. . . 






do. 


70 


20.8 


425 


395 




Westinghouse 






do. 


70 


34-1 


1,074 




1,129 


do. 






do. 


70 


34-4 


1,151 




1,190 


New York . . 






do. 


70 


32.1 


1,164 




1,376 


do. . . 






do. 


70 


33.6 


1,227 




1,328 


25 W.,25 N. Y. 




do. 


70 


20.7 


413 


■ 387 




do. 




do. 


70 


20.6 


402 


380 




25 N. Y.,25 W. 




do. 


70 


20.1 


420 


416 




do. 




do. 


70 


21.3 


472 


419 




25 W.,25 N. Y. 




do. 


70 


33.9 


1,182 




1,257 


do 




do. - 


70 


35.1 


1,285 


. . . 


1,278 


25 N. Y., 25 W. 




do. 


69.5 


34.7 


1,331 




1,344 


do. 




do. 


70 


35.3 


1,385 




1,362 


Westinghouse 




Full Service 


70 


20.1 


1,104 


1,096 




New York . . 




do. 


70 


19.9 


1,103 


i,iii 




Westinghouse 




do. 


70 


341 


2,478 




2,584 


New York . . 




do. 


70 


33-3 


2,379 




2,570 


25 W.,25 N. Y. 




do. 


70 


21.3 


1,239 


1,131 




25 N. Y.,25 W. 




do. 


70 


23.9 


1,473 


1,129 




25 W.,25 N. Y. 




do. 


70 


34-9 


2,604 




2,616 


25 N. Y.,25 W. 




do. 


70 


34-4 


2,618 




2,692 


Westinghouse 






Emergency, preceded by 
6-lb. service at 900 ft. 


70 


20.4 


368 


355 




do. 






do. do. 


70 


20.2 


361 


354 




New York . 






do. do. 


70 


20.5 


481 


461 




do. 






do. do. 


70 


20.1 


425 


421 




Westinghouse 






do. do. 


70 


31.9 


964 




1,153 


do. 






do. do. 


70 


33-9 


1,122 




1,194 


New York . 






do. do. 


70 


33.4 


1,224 




1,332 


do. 






do. do. 


70 


34.2. 


1,350 




1,408 


25 W.,25 N. Y. 




do. do. 


70 


21,2 


404 


364 




do. 




do. do. 


70 


21.3 


415 


370 




25 N. Y.,25 W. 




do. do. 


70 


24.1 


674 


488 




do. 




do. do. 


70 


19.9 


463 


467 




25 W.,25 N. Y. 




do. do. 


70 


34.6 


1,234 




1,261 


do. 




do. do. 


70 


34.3 


1,206 




1,253 


25 N. Y.,25 W. 




do. do. 


70 


33.5 


1,276 




1,382 


do. 




do. do. ' 


70 


29.9 


989 




1,313 


I9W.,4N.Y.,27W. 


do. do. 


70 


21. 1 


429 


390 




do. 


do. do. 


70 


20.4 


400 


386 




19N.Y.,4W.,27N.Y. 


do. do. 


70 


20.3 


456 


445 




do. 


do. do. 


70 


19.2 


391 


418 




29W.,4N.Y.,I7W. 


do. do. 


70 


33.0 


1,106 




1,237 


do. 


do. do. 


70 


34-5 


1,228 




1,262 


29N.Y.,4W.,I7N.Y. 


do. do. 


70 


34-1 


1,369 




1,436 


do. 


do. do. 


70 


33.8 


1,335 




1,423 



TABLE No. XXXVIIL— Continued. 



Arrangement 

of 

Brakes. 



3 W.,3 N. Y.,22 W., 

22 N. Y. 

do. do, 

3N.Y.,3W.,22N.Y., 

22 W. 

do. do. 

3 W.,3 N. Y.,22 W., 

22 N. Y. 

do. do. 

3N.Y.,3W.,22N.Y., 

22 W. 

do. do. 

Westinghouse . . 

New York . . . 
25W.,25N. Y. 
25N. Y.,25W. 
I9W.,4N. Y.,27 W. 
I9N.Y.,4W.,27N.Y. 
ioW.,ioN.Y.,i5W., 

15 N. Y. 
10 N. Y., 10 W., 15 

N. Y., 15 W. 
10 W., 10 N. Y., 15 

W., 15 N. Y. 
10 N. Y., 10 W., 15 

N. Y., 15 W. 
10 W., 10 N. Y., 15 

W., 15 N. Y. 
10 N. Y., 10 W., 15 

N. Y., 15 W. 
10 W., 10 N. Y., 

W., 15 N. Y. 
10 N. Y., 10 W., 

N. Y., 15 W. 
10 W., 10 N. Y., 

W.,15 N. Y. 
10 N. Y., 10 W., 

N. Y., 15 W. 
Westinghouse 
New York . . 
Westinghouse 
New York . . 

Westinghouse 

New York . . 
25 W.,25 N. Y. 
25 N. Y., 25 W. 
I9W.,4N. Y.,27W. 
I9N.Y.,4W.,27N.Y. 



15 



Character 

of 

Application. 



Emergency, preceded by 

6-lb. service at 900 ft. 

do. do. 



do. 
do. 
do. 
do. 
do. 



do. 
do. 
do. 
do. 
do. 



do. do. 

Emergency, preceded by 

6-lb. service at 300 ft. 

do. do. 

do. do. 

do. do. 

do. do. 

do. do. 

Emergency, preceded by 

6-lb. service at 100 ft. 



do. 



do. 



Emergency, preceded by 
6-lb. service at 150 ft. 

do. do. 

Emergency, preceded by 
6-lb. service at 200 ft. 



Emergency, preceded by 
6-ib. service at 250 ft. 



do. 



do. 



Emergency, preceded by 
, 6-lb. service at 350 ft. 



do. 



do. 



Emergency 

do. 

Full Service 

do. 

Emergency, preceded by 

6-lb. service at 300 ft. 

do. do. 

do. do, 

do. do. 

do. do. 

do. do. 



70 

70 

70 

70 

70 

70 

70 

70 

70 

70 
70 
70 
70 
70 

70 
70 
70 
70 
70 
70 
70 
70 
69.5 

70 

90 
90 
90 
90 

90 

90 
90 
90 
90 
90 



21.7 
21.3 
19. 1 
20.3 
32.9 
34.0 
33.4 
33.6 
21.3 

19.9 

21.0 
20.1 

21. 1 

20.2 

19.9 



21. 1 

20.4 
20.4 
20.8 
22.2 



19.5 
19.6 

34-7 
34.6 

33.2 
33.8 



20.4 
20.2 
19.8 
20.0 



441 
412 
383 
459 
1,126 

1,197 

1,257 

1,324 

420 

488 

439 
512 
488 
565 
390 

518 
569 
529 
496 
533 
473- 
512 
421 
464 

935 
1,024 
2,064 
2,170 

367 

424 

347 
411 
373 
426 



380 
367 
4M 



373 
492 
402 
508 
433 
555 

394 
514 
518 
5" 
479 



395 
(389) 
512 

438 

480 



^^^^^^^ Air Brake Tests 



THE 

SANG HOLLOW 

TESTS 



applications in this series alone was run 
at 35 miles per hour and the balance in 
20 miles per hour. 

All but two of the tests are recorded as having been made with the 
intended trainpipe pressure, so that the complications that might arise 
from variations in this pressure are almost entirely eliminated. Each 
length of stop was corrected from variations of speed from that intended 
and the results of the various tests are given herewith in table No. 
XXXVIIL 

In making the corrections for distances traveled by the train at the 
observed speed, the distances were assumed to vary inversely as the 
square of the speed. Corrections in distances on account of variations 
in cylinder pressure were made on a basis that the distance traveled is 
inversely as the mean cylinder pressure. As stated before, this cor- 
rection was practically eliminated in reference to the stops under consid- 
eration, due to the fact that the trainpipe pressure was, generally speaking, 
very closely to that desired. For the sake of comparison the data in 
the foregoing table was segregated according to the applications of the 
brake, thus showing more clearly the effect produced by an intermixture 
of the two systems. 

Emergency Application, 

The results found for the emergency stops made with a trainpipe 
pressure of 70 lbs., are shown in table No. XXXIX. 

Table XXXIX. 



Arrangement of Brakes. 


20 Miles per Hour, 
Distance, Feet. 


35 Miles per Hour. 
Distance, Feet. 


50 Westinghouse 


355-5 

396. 

383.5 

417-5 


"59-5 

1352. 
1267.5 

1353. 


50 New York 

25 Westinghouse ) 


25 New York \ 
25 New York ) 


25 Westinghouse \ 



In the above table the stops at 35 miles per hour were somewhat 
unsatisfactory since the mean stop of the Westinghouse and New York 



THE 

SANG HOLLOW 

TESTS 



Air Brake Tests ^"^^^^'^ 



brakes each alone was an average of two 
runs only, one of which exceeded the 
other by about 5^. The relative length 
of stops, therefore, for this speed are not altogether reliable and too 
much importance should not be attached to them. This is to be 
regretted as this feature of the tests was one of the most important for 
satisfactory determination and should have been represented by the 
average results of a large number of stops. 

Full Service Application, 
Only one stop of each kind was made for this series, so that a com- 
parison of results is useless, and a separate table of this application is 
omitted. 

Emergency, Preceded by 6-lb. Service Application at goo Ft, 
It was intended that the preliminary service application should be 
made with a 6-lb. trainpipe reduction in all these tests. This reduction, 
however, varied considerable, although it averaged about 6 lbs. As a 
result of these variations, the cylinder pressure, due to the preliminary 
apphcation, varied also. The results of these tests are given in the 
following table : 

Table XL. 



Arrangement of Brakes. 


20 Miles per Hour. 
Distance, Feet. 


35 Miles per Hour. 
Distance, Feet. 


50 Westinghouse 

50 New York 


354-5 

441. 
367. 

477.5 
388. 

431. 5 

373-5 
430.5 


II73.5 

1370. 
1257. 
1347-5 

1249.5 
1424.5 
1266. 
1397. 


25 Westinghouse, 25 New York .... 
25 New York, 25 Westinghouse .... 

19 W., 4 N. Y., 27 W 

19 N. Y., 4 W., 27 N. Y 

29 W., 4 N. Y., 17 W 

29 N. Y., 4 W., 17 N. Y 

3 W., 3 N. Y., 22 W., 22 N. Y. . . 

3 N. Y., 3 W., 22 N. Y., 22 W. . . 



In each stop made with 3 Westinghouse brakes, followed by 3 New 
York, and then 22 Westinghouse, followed by 22 New York, the emer- 
gency jumped the 3 New York brakes, so that quick action occurred in 
all Westinghouse brakes, but on none of the New York brakes. No 



^^^^^^^ Air Brake Tests 



THE 

SANG HOLLOW 

TESTS 



other case occurred in any of the tests 
where quick action in the Westinghouse 
brakes was not interrupted and discon- 
tinued by following the intervening New York brakes. In stops where 
25 Westinghouse brakes preceded 25 New York brakes, quick action 
occurred on all of the Westinghouse brakes, but on none of the New 
York brakes, thereby causing excessive shocks to the back end of the 
train. 

Emergency Application Preceded by 6-lb. Application at joo Ft, 
These stops were all made for a speed of about 20 miles per hour. 
Only one stop was made with each combination of brakes, and the 
distances traveled cannot, therefore, be assumed with certainty. The 
results of these tests are given in Table No. XLI. 

Table XLI. 



Arrangement of Brakes. 


Distance in Feet. 


CO AVestinghouse 


373 
492 
402 
508 
443 
555 


50 New York 


25 Westinghouse, 25 New York 

25 New York, 25 Westinghouse 


19 Westinghouse, 4 New York, 27 Westinghouse 

19 New York, 4 Westinghouse, 27 New York 



It will be observed in the above table that the length of stop where 
25 Westinghouse preceded 25 New York brakes, was about 9^ longer 
than for 50 Westinghouse brakes alone; whereas, where 19 New 
York brakes preceded 4 Westinghouse, and then 27 New York 
brakes followed, the length of stop was nearly 49^ greater. In these 
tests the erratic behavior of the New York brakes, when in com- 
bination with the Westinghouse brakes, was very manifest. The char- 
acter of the application throughout the train and the mean final 
cylinder pressure was the same where 50 New York brakes were used 
alone ; where 2 5 New York preceded 2 5 Westinghouse, and where 
19 New York were followed by 4 Westinghouse and 27 New York ; 
but the length of stop for each of these combinations differed largely. 



THE 

SANG HOLLOW 

TESTS 



Air Brake Tests ^"^^^^^ 



Emergency, Preceded by 6- Lb, Service 

Application at Various Short 

Distances, 

All of the stops in this series were made at a speed of about 20 
miles per hour, and the make-up of the train was in every case either 
I o Westinghouse followed by i o New York, 1 5 Westinghouse and 
1 5 New York, or 10 New York followed by i o Westinghouse, i 5 
New York and 1 5 Westinghouse. The results are shown in table 
No. XLIL 

Table No. XLII. 



Service Precedes 
Emergency. 


Arrangements of Brakes. 


Distance in 


Feet. 


100 


feet. 


10 W., 10 N. Y., 15 W., 15 


N. Y. 


394 




100 


do. 


10 N. Y., 10 W., 15 N. Y., 


15 W. 


514 




150 


do. 


10 W., 10 N. Y., 15 W., 15 


N. Y. 


518 




150 


do. 


10 N. Y., 10 W., 15 N. Y., 


15 W. 


511 




200 


do. 


10 W., 10 N. Y., 15 W., 15 


N. Y. 


479 




200 


do. 


10 N. Y., 10 W., 15 N. Y., 


15 W. 


498 




250 


do. 


10 W., 10 N. Y., 15 W., 15 


N. Y. 


395 


(389) 


250 


do. 


10 N. Y., 10 W., 15 N. Y., 


15 W. 


512 




350 


do. 


10 W., 10 N. Y., 15 W., 15 


N. Y. 


438 




350 


do. 


10 N. Y., 10 W., 15 N. Y., 


15 W. 


480 





The first stop shown in table No. XLIL was practically a regular 
emergency stop, since no triple valves of the New York Brakes had 
been acted upon by the service reduction of trainpipe pressure before 
the effect of quick action in the emergency application reached them. 
In all of the stops where New York brakes were in the lead, quick 
action failed to apply throughout the train similarly to the preceding 
series. Some very erratic features in the operation of the brakes was 
also noted in the stops of these series. 

Conclusions, 

Ordinary emergency stops were about 12^ longer with the New 

York than with the Westinghouse brake equipment. In emergency 

stops preceded by service application, those made with the New York 

brakes were found to be from 17 to 32^ longer than those made with 



^""^''^^ Air Brake Tests 



THE 

SANG HOLLOW 

TESTS 



the Westinghouse brakes, depending upon 
the conditions. Where the New York 
brakes were mixed with the Westing- 
house, the operation of the combination was generally better than 
when the New York brakes were used alone, if the Westinghouse 
brakes are next the engine. When New York brakes were next 
to the engine, very erratic and incomprehensible action took place. 
In all cases of emergency preceded by service applications where New 
York brakes were so placed, the quick-action feature of both kinds of 
brakes v/as destroyed. What took place was a full service application 
under conditions which caused that application to be made very 
promptly and effectively. An emergency stop with the Westinghouse 
brakes, at a speed of 20 miles per hour, after a previous application 
at 100 ft., was made in a distance of 355 feet. With 10 New 
York brakes preceding i o Westinghouse, i 5 New York and 1 5 West- 
inghouse, the stop was 514 ft., 45^ greater than the Westinghouse 
stop, where the service application preceded the emergency by 300 
feet. The stop at 20 miles per hour, with 19 New York brakes, 
followed by 4 Westinghouse and 24 New York, exceeded the stop 
of 50 Westinghouse by 49^. Since many of these stops were single 
ones and not an average of a number of each kind, the above men- 
tioned results cannot be assumed with certainty, but the results showed 
the erratic action of the brakes when the two systems are mixed 
together. 



)0( 



THE SHIPROAD TESTS. 

These tests occurred in October, 1894, upon the main Hne of the 
Pennsylvania Railroad, just west of Philadelphia, and are chiefly interest- 
ing as being the first tests made upon what is known as the high-speed 
brake. Whereas the results may not have been as accurately obtained 
as those of subsequent trials, they showed most convincingly the great 
advantage of the high-speed apparatus, and were very useful in bringing 
to the attention of railways, as well as pointing out to the brake com- 
panies, such defects as may have been embodied in the primitive design 
of such auxiliary apparatus as went to make up this equipment. 

The tests were made upon a train of locomotive and 6 passenger 
coaches, and were divided into two series made upon consecutive days. 
The first series was called the preliminary test, and included several 
runs, at speeds approximating 45 miles per hour. . The trainpipe pres- 
sure was 70 lbs. for the ordinary quick-action brake, and 100 lbs. for 
the high-speed brake. The runs of the second day repeated those of 
the first, except that the speeds were raised to 60 miles per hour. 

The grade of track at the point where the tests were made was 29 
feet to the mile, descending. On both days the weather was fair and 
the rails dry. The braking-power percentage on the cars was obtained 
from indicator diagrams taken by instruments in each car. The total 
weight of the train was 564,000 lbs. 

The results of the tests are given in the following tables. Test No. 
I of each series is omitted because of the figures being untrustworthy, 
due to trouble with the recording apparatus. 

The average length of stop in feet from a speed of 45 miles per hour 
with 70 lbs., trainpipe pressure was 688.5. ^^^ average length of 
stop in feet from a speed of 45 miles per hour with 100 lbs., trainpipe 
pressure was 574. This gave a percentage in length of stop in favor 
of 100 lbs. trainpipe pressure as against 70 lbs. of 17^. 

The average length of stop at 60 miles per hour at 70 lbs. trainpipe 
pressure was 1,620 ft. The average length of stop at 60 miles per 
hour with 100 lbs. trainpipe pressure was 1,329 ft., giving a per- 
centage of average length of stop in favor of 100 lbs. as against 70 lbs. 



^""^''^^ Air Brake Tests 



THE SHIPROAD 
TESTS 



trainpipe pressure, of i8^. The average 
length of stop with 1 09 lbs. trainpipe pres- 
sure was 1,167 ft., so that the percentage 
of length of stops in favor of 109 lbs. as against 70 lbs. trainpipe pressure 
was 28^. 

Table XLIII. — Preliminary Tests of October i, 1894, with High-Speed 
Brake Train, Consisting of Locomotive and Six Passenger Cars. 













(U J 






CU w 


a, . ♦; 
























i 


X 


2. 





c c 






53=2; 


^3t 


•3 


3 

a, 


CD 




.5 c 
^ 

S C/3 




fl 


^ .. 

I- 

0,^ 


c 6 

bO 

is 


C u 
C3 




7, 'u 


h 


c 
"t3 


"rt 


P 


"rt 


C « 


^(^ 


pa c 




-*3 s- 




h 


< 


h 


< 




Ji4 

ci 


oh 




3 vr, C 


2 


71 


4714: 


21 


776 


52.2 


86.8 


76.3 


702 




3 


69 


45 K 


i8>^ 


697 


52. 


86. 


75-7 


675 




4 


100 
104 


46^ 




584 


76.2 


102.5 
106.4 


94-5 
97. 




567 


5 


610 


75-4 


600 


6 


100 


47 


15X 


601 


77.1 


105. 


96.5 




555 



Table XLIV. — Test of October 2, 1894, with High-Speed Brake Train, 
Consisting of Locomotive and Six Passenger Cars. 













U aj 






cu *^ 


a, . ■^* 


0, <-* 


B 


XI 

3 







a, 





.5 W) 

5S 

2 " 


U 
U) 


• 


2iS 

C/3 ^ Ci, 


M « 


13I 

bjo r M 




-^ 


V 


.S c 
.u 




^ .. 

I, 

ps " 




W) . 

2 •• 






T3 ^ U 


h 


"E, 

C 


< 


(U 

6 
h 


< 


6X) C 

c u 




^h 

h 


age 

c3 '^h 


c3«h 


CJ«h 


2 


68 


60^ 

58|< 
61X 


31X 
30.^ 
31 
25 


1,697 
1,634 
1,584 

1,372 


51.6 

52. 
52. 

79-3 


85.2 
87.6 

87. 
101.8 


75. 
76.8 
76.4 
95- 


1,618 






3 
4 
5 


71 

71 

100 


1,576 

1,668 












1,319 




6 


104 


61/2 


25)^ 


1,361 


79.8 


100.6 


94-3 




1,344 




I 


105 


61/2 


24 


1,330 


81. 1 


100.9 


94-9 




1,324 




8 


108 


5iij4 


22 


1,125 


82.8 


107.7 


100. 1 






1,179 


9 


109 


6iX 


22>^ 


1,202 


83.2 


108. 


100.5 






1,155 



I 



NASHVILLE LOCOMOTIVE BRAKE TESTS. 

These tests were carried on upon the Nashville, Chattanooga & St. 
Louis Railway at Nashville, Tenn., under the supervision of the 
Assistant General Manager of that line and were reported by the Press 
and Printing Committee of the Air Brake Association in 1895. The. 
tests were made for the purpose of ascertaining the difference in length I 
of stop obtained if the engine was reversed when the air brakes were 
applied and the wheels locked, from that if the air brakes alone were used. 

One of the locomotives of the road was especially equipped with 
the latest style of push-down cam brake having 75 per cent, braking 
power, and the engine w^as put into such good repair and condition 
that the desired data would be complete and reliable. The tests were 
carried on for six days, making nearly 100 runs, and the records given 
in the following table are averages taken from the total number. 

Data. — Braking power on driving wheels of locomotive, 70 per 
cent.; braking power on wheels of tender 100 per cent, of light 
weight ; braking power on wheels of N. C. & St. L. coaches 90 per 
cent. ; braking power on wheels of Pullman sleeping cars, varied from 
40 per cent, to loi per cent. 

A trip was placed in the track to open the trainpipe. A second trip 
was used to open the signal pipe, thus giving the engineer a signal to 
reverse the engine simultaneously with the application of the air brakes. 
Engine w^as equipped with a Boyer speed recorder which was tested 
each day. 

The following order of operation was followed : First, brake 
applied ; second, engine reversed ; third, sand lever opened. 

Track was level, and in best possible condition. 

Tests were made under the most favorable circumstances. 

The deductions to be drawn from the tests may be summed up as 
follows : 

First : — The shortest reliable stops will be made by retarding power 
which is most quickly developed and maintained to the highest possible limit 
during the entire stop, consistent with safety from skidding wheels, such 
as the air brakes give, and is confirmed by records in the following table; 



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NASHVILLE LOCO- 
MOTIVE BRAKE 
TESTS 



Air Brake Tests ^"^'^^^ 



Second : — The retarding power given 
by the back pressure in the steam cylin- 
ders when the engine is reversed fluctuates 
and is too inconstant to be relied upon. As soon as the back pressure 
developed is greater than the adhesion between the wheel and the rail, 
the driving wheels will revolve backwards and lose all retarding force. 
Trials were made throwing the reverse lever ahead sufficient length of 
time to release the wheels and get them running forward again, but so 
much time and distance were lost in this effort that the stop exceeded 
in length that made by leaving the lever in the back motion after it had 
been placed there. The length of stop was the same, whether the 
cylinder cocks were opened or closed. When the engine was reversed 
without brakes the wheels did not lock rigidly. 

Third : — The length of stop made with air brakes applied and 
engine reversed, while being longer and extremely injurious to the tire 
from skidding and making flat spots, is not as long as was expected, but 
is satisfactorily accounted for by the fact that as the flat spot grew 
during the stop, and, with the heat developed, gave a larger and better 
surface to the rail for adhesion. The stop was longer than those made 
with the brakes alone and was very costly. The results of these tests 
should determine the inadvisability of using the reverse lever in con- 
junction with air brakes. 

Fourth : — Sand is a good thing if judiciously used, but if used after 
wheels are skidding will produce flat spots and will not unlock the 
wheels after they commence sliding. A superabundance of sand is not 
quite so effective as a moderate amount. The best results were had 
from a rail upon which sand remained from a previous stop. 

Upon a rail thoroughly '^saturated " but not burdened with sand, 
it was impossible to slide the wheels under the conditions which pre- 
vailed. On straight track, if sand reached the rail before full retarding 
power was developed by the air brake and the back pressure in the 
steam cylinders with engine reversed, wheels would not lock or slide ; 
but on curves where engine rolled about, the adhesion between the 
wheel and rail, even when increased by a free flow of sand, would be 
broken and the drivers would lock and slide with disastrous results. 



^"^^^^^ Air Brake Tests 



NASHVILLE LOCO- 
MOTIVE BRAKE 
TESTS 



Several of the ^'Unexpected Emergen- 
cies/' as recorded in Nos. 29 and 31, 
were made on curves, but the majority 
were made on straight track. If sand valves were opened before brakes 
were applied and engine reversed, the wheels would not lock in 
'^ Expected Emergencies," but the delay in applying retarding power 
w^ould slightly lengthen the stop over that had by the use of the air 
brakes alone. 

Fifth: — In making the '^ Unexpected Emergency" stops the 
drivers would invariably lock when engine was reversed and flat stops 
were had. In one instance the engineer, who was unusually expert 
and active, got tangled up with the reverse lever and did not succeed 
in reversing the engine with his first eiFort. The train ran considerably 
farther than the length of stop given in No. 29. The time consumed 
by the engineer in applying brakes, reversing engine, and opening sand 
valves w^as i ^ seconds, which is very much quicker than the feat can be 
accomplished ordinarily. When also considering the fact that a certain 
length of time is consumed by the engineer recovering from the bewilder- 
ment of '' Unexpected Emergencies," it would seem impossible for him 
to get sand on the rail before the wheels would lock if he were to 
reverse his engine after applying the brake. The '* Expected Emergency' ' 
given in No. 30 was a good stop, but engineers seldom meet expected 
emergencies. 

Sixth : — The Pullman cars were not braking as they should, as the 
piston travels on all cars varied from 10 to 12 inches. After the slack 
was taken up better stops were had. The percentage of braking power 
on these cars had an abnormally wide range. The condition of the 
brake apparatus on the N. C. & St. L. coaches, which were taken from 
service without any preparation for the test, speaks eloquently for the 
system of maintenance of brakes on the N. C. & St. L. R'y. Tests 
Nos. 32 and 33 were made by backing the car with the engine until 
the desired speed was developed, then the angle cock was closed, 
engine detached, and hose uncoupled. The angle cock was opened at 
a certain point, from which the stop was taken. 



THE ABSECON TESTS. 

The object of these tests was to obtain reliable data of the stopping 
power of the high-speed brake, as compared with the ordinary quick- 
action brake on passenger trains. In view of the fact that in 
previous trials speeds were not determined by accurate methods, it was 
decided that in making the present tests the following general method 
should be followed : 

First : — Stops should be made on a practically level track ; the 
brakes to be always applied at the same point. 

Second : — An accurate method should be used to record the speed 
of the train, not only at the moment of the brake application, but also 
during the whole stop, so as to determine the rate of retardation during 
the stops from different speeds. 

Third : — That stops should be at progressive speeds, at as nearly as 
possible 20, 30, 40, 50, 60, 70, etc., miles per hour. 

Fourth : — That the train should be variously made up, so as to rep- 
resent as far as possible the different classes of trains used in actual 
service. 

The trials were made on the Atlantic City division of the West 
Jersey & Sea Shore Railroad, on the long tangent which terminates 
near Absecon. All stops were made on the southbound track. The 
emergency applications were automatically made by a trip block placed 
beside the track at the zero point or trip. The stopping track was 
approximately level, but the approaching grades were, as a rule, in 
favor of the train attaining speed. Electric contact breakers were 
arranged to break and again make the circuit. The circuit breakers 
were placed in a series beginning 396 ft. in advance of the zero 
point or trip, and continuing 5,200 ft. after passing that point. 
Those in advance of the zero point were spaced 66 ft. apart, while 
those after passing the trip were spaced 100 ft. apart. In the same 
circuit with the breakers were the necessary batteries and two chrono- 
graphs, each arranged to record on a paper-covered drum, revolving at 
a uniform rate, the time interval between the breaks in the track circuit. 
Accurate circuit breaking clocks recorded the time intervals on the same 



14' Pipe Tap j ^-p J: L-r^ 




Fig. Ill 
Westinghouse High-Speed Brake Reducing Valve. 



THE ABSECON 
TESTS 



Air Brake Tests ^"^^^^^ 



paper, so that the actual elapsed time 
between any two breaks could be directly 
measured. 

As the train passed each circuit breaker a flexible wiper placed on the 
tender caused a break, and each of these breaks were instantly recorded 
by the chronographs. Thus by the time interval between passing the 
circuit breakers in advance of the zero point, the initial speed of the 
train before the brake application was determined, and its retardation 
during the stop was shown by the lengthening intervals of time required 



to pass each loo ft. space. 




1^ Pipe Tap^"-^ ^^ To Brake Cylinder » 

Fig. 113 * 

In table XLV. will be found the weight of the engine on the truck 
and on the other wheels ; also the weight of the tender ordinarily 
loaded, and of each car in the train, together with the percentage of 
weight on the rail which was braked. 

The feature which distinguishes the high-speed brake from the ordi- 
nary quick-acting one, is the reducing valve shown in Figs. 1 1 1 and 112. 



^""^''^^ Air Brake Tests 



THE ABSECON 
TESTS 



One such valve is attached to each brake 

cylinder. Its function is to allow a 

momentary increase of pressure over that 

which is permissible at the time of the stop ; this pressure gradually 

leaking off. 

As the tests were to prove the relative performance of the quick- 
acting brake, carrying 70 lbs. trainpipe pressure, and the high-speed 
brake, carrying 1 10 lbs. trainpipe pressure, at different speeds and with 

Table XLV. — Arrangement and Weights of Trains and Average 
Percentage of Braking Power. 



Arrangement of Train. 



Total 

Weight, 

Lbs. 



Percentage of 
I Weight Braked, 
M. E. P. IN Cylinder. 



88 Lbs. 



Locomotive, 6 Coaches, and Chair Car . 

Locomotive and 6 Coaches 

Six Coaches only 

Locomotive, 3 Coaches, and Chair Car 

Locomotive and 3 Coaches 

Locomotive only 



774,650 


72.8 


667,050 


73.1 


372,350 


92.9 


588,700 


66.1 


481,100 


65.5 


294,700 


48.3 



no. I 

III.O 

140.8 

100.4 

99-4 

73-3 



various arrangement of trains, the full programme was made of the tests 
proposed, and it was decided that the tests should be made at a series 
of progressive speeds, the same speeds, as far as practicable, being 
reached with each brake. The speeds desired were those commencing 
at 20 miles per hour and increasing by steps of 10 miles per hour, 
until the highest attainable one was reached. 

The following arrangements of train were decided upon : 

1. Locomotive, 6 coaches, and i chair car. 

2. Locomotive and 6 coaches. 

3. Locomotive, 3 coaches, and i chair car. 

4. Locomotive and 3 coaches. 

5. Locomotive alone. 

The weights of each of these trains, and the percentage braked with 



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''''^''^^ Air Brake Tests 



THE ABSECON 
TESTS 



the cylinder pressures attained in both 
the quick-acting and the high-speed brake, 
are shown in table XLVI. 

An engine was taken from service and equipped with brakes on the 
trailing wheels in addition to those on the drivers and truck. By this 
arrangement the brakes on the drivers and trailers were equalized and 
operated by two 1 2 -in. cyhnders, but a separate cylinder, triple valve and 
reservoir were applied to the engine truck brake. The engine was also 
equipped with the trip cock used by the Westinghouse Air Brake Com- 
pany for automatically venting the trainpipe during the emergency 
stops. A special trainpipe gauge was placed in the engine cab, as well 
as the recording voltmeter of an electric speed indicator. The tender 
was equipped with a high-speed reducing valve. 

Each of the 6 coaches was equipped with a reducing valve suitable 
for a 1 2 -in. cylinder. Five of the cars were furnished with brake 
cylinder pressure indicators, supplied by the Westinghouse Air Brake 
Company. These are simply steam engine indicators, in which the 
ordinary paper drum is replaced by a larger one driven by a clock 
escapement. The indicator cards show the pressure per square inch on 
the ordinates and the seconds on the abscissas. These ^w^ cars were 
also equipped with cylinder and reservoir gauges, and two of the cars 
with trainpipe gauges. 

The Pullman car was equipped with a reducing valve, but not with 
any gauges or indicators. The brake equipment of the entire train was 
overhauled before trial, but, as it proved, some of the triple valves were 
not in the best possible condition. In this respect, the train fairly repre- 
sented, as a whole, conditions which are readily duplicated in service. 
All the cars, as well as the tender, were equipped with the ordinary 
cast-iron brake shoes, which had been worn to a fair bearing before 
the trials began. The shoes which were worn out during the trials 
were replaced by others partly worn, to remove the hard external scale. 
The shoes on the engine were steel castings ; those on the trailing 
wheels being new. 

Owing to the presence of automatic signals, approximately i mile 
apart, the train was not allowed to back past any signal. It could. 



THE ABSECON 
TESTS 



Air Brake Tests ^""^''^^ 



however, back about 2,000 ft. from the 
cabin, and in this distance it was possible 
to reach speeds of 20 and 30 miles per hour 
with the full train. Above these speeds it was necessary to cross over at 
Absecon and back on the northbound track to the point of starting. As a 
rule, 40 and 50 miles could be made from a distance of 1.2 miles ; 60 
and 70 miles from a distance of 3.8 miles, and 80 miles per hour from a 
distance of 9 miles, and the higher speeds from a distance of i 5. i miles. 

It was decided that the acceleration at the start should be as rapid as 
possible, and steam was shut off in advance of reaching the marked 
track, so that the train, as nearly as possible, would drift at uniform 
speed, over the six spaces, each of 66 ft., in advance of the zero or 
trip point. At the trip point, the stop-block placed along the track 
struck the trigger which kept the emergency valve on the engine closed. 
This suddenly opened the trainpipe and made the emergency application. 
In service apphcations, the opening in this pipe was plugged, and the 
applications were made by hand in the usual manner. 

The wiper on the tender struck each contact breaker as it passed ; 
the circuit being immediately reestablished, so that the breaks in the 
track circuit would be recorded on the chronograph drum in the cabin. 

The braking power of the locomotive and tender was considerably 
lower than standard (unfortunately representing a condition which is very 
often met with in practice when the brakes are not carefully maintained). 
For that reason the percentage of braking power for the smaller trains 
was much less, the weight of the engine being a so much greater per- 
centage of the total weight. 

The Pullman car also happened to have a variation from the stand- 
ard leverage, giving a much lower braking power on this car than is 
usual, the effect of which is so interestingly shown in the records. As 
the train was selected pretty much at random, in order to represent such 
conditions as might be met with in service, the leverages were allowed 
to remain as they were found. 

The results have been arranged as shown in the accompanying curves 
and tables. 

Fig. 113 shows the velocity curves from the moment that the brake 









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inoH -lafl y^UK "I paadg 



THE ABSECON 
TESTS 



Air Brake Tests ^^^^-^^^ 



is applied till the train stops, for various 
speeds from 56 to 80 miles per hour for a 
train consisting of engine, 6 coaches and i 
chair car. The trainpipe pressure is noted in each curve, and it w^ill be 
remembered that 110 pounds indicates the high-speed brake, vv^hile 70 
pounds indicated the quick-action brake. Vertical distances represent 
the speed in miles per hour and horizontal distances show the distance 
in feet traveled from the point w^here the brake w^as applied. Thus it 
v^ill be seen that with an initial speed of 80 miles per hour, after the 
train went 2,000 feet from the point where the brake was apphed, the 
speed was reduced in the case of the high-speed brake to 30 miles 
per hour, whereas with the quick-action brake it was reduced to 45 
miles per hour. The difference in the length of stops, 22^ per cent., 
is also shown. 

Fig. 1 1 4 shows the velocity curves for a train of engine and 6 
coaches without the chair car. Fig. 1 1 5 is the same for a train con- 
sisting of engine, 3 coaches, and i chair car, and Fig. 1 1 6 for a train 
consisting of engine and 3 coaches. Fig. 1 1 7 shows same for engine 
alone. 

Fig. 118 shows a comparison of the lengths of stops, with emer- • 
gency application of the brake, of the high-speed brake and the 
quick-action brake for the locomotive alone. In this diagram vertical 
dimensions show the speed at which the locomotive was moving 
when the brake was applied and horizontal distances represent the 
number of feet traveled before it came to a stop. The full line repre- 
sents the stop with quick-action apparatus, and the dotted line 
with high-speed attachment and pressure. It is well to note 
that the difference in lengths of stop between these two curves for 
any given speed is the horizontal distance between them at the ver- 
tical height indicated for that speed, as given at the left of the 
diagram. For instance ; at 80 miles per hour, the length of stop for 
the high-speed brake is shown as 3,500 feet; for the quick-action 
brake, 4,200 feet. For that speed, therefore, the high-speed brake 
made a stop of 700 feet, or over ^ of a mile less than the quick- 
action brake, so that the high-speed stop was 83 per cent, of the 





























































































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THE ABSECON 
TESTS 



Air Brake Tests ^^-^^-^^^ 



quick-action stop, and the distance saved 
by the use of the high-speed brake was 20 
per cent. At the higher speeds the length 
of stop with quick-action was longer than the length and scale of this 
diagram will permit to be placed on it, so the curve has been broken 
at B and continued below from B to C . 

Fig. 119 is the same diagram as Fig. 118, only in reference to a 
train of engine, 6 coaches, and i chair car. Fig. 120 is for a train 
of engine, 3 coaches and i chair car. Fig. 1 2 1 shows com- 
parison of the stops made by trains of different make-up with the quick- 
action brake, using 70 lbs. trainpipe pressure ; and Fig. 122 shows a 
similar comparison with the high-speed brake using iio lbs. trainpipe 
pressure. 

Comments, 

From the curves it is apparent that the coaches were more effect- 
ively braked than the engine, tender, or the chair car. 

In this connection special attention is called to the ' *■ Parting Test ' ' 
runs recorded as Nos. 6 and 7, Figs. 121 and 122. In these two 
runs the train consisted of the 6 coaches and the locomotive. Just 
before the application of the brake the tender was uncoupled, so that 
each section could be stopped at different points. The results obtained 
were that on the run carrying 70 lbs. trainpipe pressure at a speed 
of 67.8 miles per hour, the 6 cars in the train ran 1,416 ft., while 
the engine and tender ran 2,828 ft., almost twice as far. In the run 
with IIO lbs. trainpipe pressure and an initial speed of 6^.^ miles 
per hour, the coaches stopped in 1,021 ft., while the engine and 
tender ran 2,360 ft., or more than twice as far. 

It must be borne in mind that this proportion of length of stop 
between engine and train does not at all represent standard conditions ; 
it chanced that this engine and tender selected had a braking power of 
only 48 per cent., due to the fact that the brakes had not been properly 
maintained. The usual practice is to brake the locomotive to 75 per 
cent, and the passenger coaches to about 90 per cent, of their light 
weight, so that in any case the braking power of the locomotive would 
only be about 8 3 per cent, of that of the passenger coach. Consequently 



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Train > _ . _ , 

Locomotive! P^i'ting Tests 


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THE ABSECON 
TESTS 



Air Brake Tests ^^^^-^^^ 



under the very best conditions in such 
parting tests as above described, the 
locomotive w^ould show at least a 20 per 
cent, longer stop than the train. 

Wheel Skidding. 

The weather conditions were, in general, fair and the rail good. 
Even with the rail partly wet, no sliding of any consequence could be 
attributed to it. The programme did not provide for the use of sand 
during the stops, but through inadvertance the rail was sanded fully 
during one stop at 50.1 miles per hour, and another at 60.1 miles per 
hour. The difference in the length of the stop with and without sand 
was inappreciable, and no proof exists that the sand was markedly 
beneficial. 

Very little sliding was experienced in the earlier part of the trials, 
although the brake pressure on the coaches during the first part of the 
application was 143 per cent, of the weight on the rail. As the tests 
progressed, the sliding on some of the cars increased slightly, although 
apparently the conditions of the stop did not change, but the wheels 
which had once slid seemed to be more liable to do so again. 

Results, 
The general results given in tables XL VII. and XLVIII. show the 
length of stop in feet for both high-speed and quick-action brakes for 
various speeds from 45 to 80 miles per hour, and for trains of 
different make-up. Table XLVII. gives the results as actually recorded 
and also as reduced to uniform speeds by the methods of calculation 
usually employed. The second table gives the percentage relation of 
the high-speed stop to the quick-action ; also the percentage of 
distance saved by the high-speed brake. In this last table the trains 
are placed in order of their stopping efficiency for each speed, begin- 
ning with the lowest, the speed being given in column i, and the 
make-up of the train in column 2. The length of stop in feet with 
the high-speed brake is given in column 3, and with the quick-action 
brake in column 4. Column 5 shows what percentage the high- 
speed stop was of the quick-action stop, the latter being taken as 

















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jnoiiaaj S9[iiv^ fpascig 



THE ABSECON 
TESTS 



Air Brake Tests ^""^'^'^ 



unity. Column 6 gives the percentage 
saved by the use of the high-speed brake, 
being the diiFerence between the two 
stops divided by the high-speed stop. 

The results given in these tables are plotted graphically in Fig. 123. 
The horizontal distances represent the length of stop in feet, and the 
various make-ups of train are grouped together for each speed as given 
at the left of the diagram. The make-up of train is shown by different 
lines as indicated, and the kind of brake apparatus used is shown for 

Table XLVIII. — Trains Placed in Order of Their Stopping Efficiency, * 
Relative Length of Stop in Feet, and Percentage of Same. 

^^ick Action Taken as Unity. 



Speed 

in 

M.P.H. 



45 
45 
45 
50 
50 
50 
60 
60 
60 
70 
70 
70 
80 
80 
80 



Make-up of Train. 



Engine, 6 coaches and chair car 

do. 3 do. do. do. 

do. alone , 

do. 6 coaches and chair car 

do. 3 do. do. do. 

do. alone 

do. 6 coaches and chair car 

do. 3 do. do. do. 

do. alone 

do. 6 coaches and chair car 

do. 3 do. do. do. 

do. alone 

do. 6 coaches and chair car 

do. 3 do. do. do. 

do. alone 



Length 


OF Stop 




IN Feet. 


Per 






Cent. 

of 
Stop. 


High- 


Quick- 


Speed 


Action 


Brake. 


Brake. 




560 


710 


78.8 


670 


810 


82.7 


920 


1,180 


77.9 


705 


880 


80.1 


830 


1,030 


80.5 


1,170 


1,480 


79.0 


1,060 


1,360 


78.0 


1,275 


1,615 


78.9 


1,760 


2,210 


79.6 


1,560 


2,020 


77.1 


1,880 


2,340 


80.3 


2,530 


3,065 


82.5 


2,240 


2,780 


80.7 


2,610 


3,250 


80.3 


3,500 


4,200 


83.3 



Per 

Cent. 
Saved by 
High- 
Speed 
Brake. 



26.8 
20.9 
28.3 
24.8 
24.1 
26.5 
28.3 
26.7 
25.6 
29.5 
24.5 
21. 1 
24.1 
24.5 
20.0 



each train. This figure shows at a glance the constant superiority of 
the high-speed brake, as well as the rapid increase of distance neces- 
sary to stop a train as the speed increases. It also shows that the 
superiority of the high-speed brake is almost exactly the same propor- 
tionately for all speeds. 




^"^^-^^•^ Air Brake Tests 

Conclusions, 

With an emergency application, trains 
equipped with the high-speed brake 
stopped in about 26 per cent, less distance than trains with the 
quick-action brake employing a trainpipe pressure of but 70 lbs. The 
emergency feature was available after the brake had been applied in 
service in response to a considerable reduction of trainpipe pressure. 

In service application, aside jfirom obtaining a more prompt response 
of the brakes, owing to the quicker flow of air due to the higher pres- 
sure, the high-speed brake was practically the same as the quick- 
action brake, with the further advantage that the high pressure gave 
an available reserve which made several full service applications possible 
without recharging. This feature on long grades is of the greatest value. 

With the short trains less effective braking occurred, because of 
the average braking power being less on account of the engine and 
tender forming such a large per cent, of the total weight, and being 
braked at a less percentage than the cars. Consequently, the shorter 
a train the greater the rrecessity for the use of the high-speed 
equipment, and the most complete and efficient brakes on the locomo- 
tive and tender. 

A truck brake should be on all passenger engines, and on those haul- 
ing short trains it is indispensable. It is also necessary to have the 
efficiency of the driver and tender brakes kept commensurate with mod- 
ern practice. 

The diagrams show very clearly the great increase of distance required 
to stop as the speed increases. 

The gain in efficiency of the high-speed, as compared with the 
quick-action brake, was practically constant at the different speeds at 
which comparative tests were made. 



)0( 



ATSION TESTS. 

In May and June, 1903, some comparative high-speed brake tests 
were made at the instance and under the supervision of the Central 
Railroad of New Jersey at Atsion Station. 

The purpose of these tests was to compare the Westinghouse high- 
speed brake equipment with a new and improved arrangement of the 
New York brake apparatus. This arrangement of the New York air 
brake apparatus consisted of special triple valves, in connection with 
which ordinary pop valves were used, which were set to close at 
70 lbs. pressure per square inch ; the brake on the cars being arranged 
for 60 lbs. pressure, to represent 90 per cent, braking power. The same 
train was also equipped with Westinghouse special triple valves and high- 
speed reducing valves set to close at 60 lbs. pressure per square inch ; 
the closing pressure being the same as that for which the car leverages 
were arranged. The trainpipe pressure in both systems were supposed 
to be 1 1 o lbs. 

These tests were run under almost precisely the same arrangement of 
apparatus and supervision as those of the Absecon test just described. 
A substantial cabin for housing the instruments was built at a point 
selected with reference to the attainment of the highest possible speed, 
and at a distance of 40 ft. from the track, to avoid vibration, which 
might otherwise have affected the very delicate speed-recording devices 
employed. These devices included a chronograph, a clock for beating 
seconds, and the usual electrically operated mechanism for indicating the 
exact moment when the circuit breakers, erected for over a mile along 
the track, were opened and closed by a '^sweeper" on the engine 
provided for that purpose. The record thus obtained showed the 
exact speed of the train at the instant the brakes were apphed, the rate 
of retardation during the 100 ft. following the application, and the 
length of stop in both seconds and feet. During the tests representa- 
tives of the railroad company and of both air brake companies were 
present and all figures were carefully checked and rechecked by all parties 
concerned. 



# 



Table XLIX. — Comparative Tests of High-Speed Brake 

On the Central Railroad of Neiv Jersey^ Near Atsion, Neiv Jersey^ 
May and June^ igoj. 







-a 







-0 


i -. 









rt 


^33 


1 jCi 


f ? 


3 


£ t 




S-ls 


Kind of Brake. 


u 

o 
d 


C/3 . 

< 




13 
2 ^ 


^ a, 
-a 




5^ 

c 


> 








< 


<3 


C/3 




►J 


< 


Westinghouse 


3 


78.60 


IIO.3 


2053.00 


80 


IIO 


2133.44 




Westinghouse 


3 


79.64 


IIO.5 


2108.00 


80 


no 


2137.09 


2099.96 


Westinghouse 


3 


77.92 


109.7 


1929.75 


80 


IIO 


2029.37 




New York 


3 


77.58 


109.5 


2152.25 


80 


IIO 


2270.96 




New York 


3 


78.60 


109.6 


2255.16 


80 


IIO 


2334.92 


2308.19 


New York 


3 


80.35 


109.5 


2340.75 


80 


IIO 


2318.71 




Westinghouse 


3 


70.03 


109.2 


1595.58 


70 


IIO 


1579.23 




Westinghouse 


3 


70.86 


109.6 


1572.75 


70 


IIO 


1529.99 


1554.61 


New York 


3 


69.23 


109.3 


1540.58 


70 


IIO 


1573.19 




New York 


3 


68.70 


109.5 


1537.08 


70 


IIO 


1594.23 


1582.68 


New York 


3 


69.23 


109.3 


1548.00 


70 


IIO 


1580.63 




Westinghouse 


6 


69.23 


109.6 


1262.91 


70 


IIO 


1286.31 




Westinghouse 


6 


70.86 


109.3 


1424.58 


70 


no 


1381.06 


1333.68 


New York 


6 


70.31 


IIO.O 


1566.16 


70 


no 


1552.38 




New York 


6 


70.03 


109.5 


1600.33 


70 


no 


1597.60 


1571.34 


New York 


6 


70.03 


109.6 


1566.50 


70 


no 


1564.06 




Westinghouse 


6 


59.80 


109.4 


974.75 


60 


no 


976.16 




Westinghouse 


6 


60.20 


109.4 


995.00 


60 


no 


982.82 


982.30 


Westinghouse 


6 


58.82 


109.4 


954.83 


60 


no 


987.92 




New York 


6 


59.60 


109. 1 


1014.66 


60 


no 


1026.19 




New York 


6 


59.21 


109.3 


968.41 


60 


no 


992.57 


1015.07 


New York 


6 


58.82 


109.0 


989.25 


60 


no 


1026.45 




Westinghouse 


6 


51.28 


109.0 


656.75 


50 


1 10 


618.50 




Westinghouse 


6 


51.13 


109. 1 


613.25 


50 


no 


582.03 


602.16 


Westinghouse 


6 


50.84 


109. 1 


631.83 


50 


no 


605.95 




New York 


6 


50.56 


109.3 


706.08 


50 


no 


688.98 




New York 


6 


49.18 


109.4 


650.08 


50 


no 


670.90 


670.95 


New York 


6 


50.42 


IIO.O 


664.00 


50 


no 


652.98 




Westinghouse 


3 


79.30 


70.16 


2804.66 


80 


70 


2859.76 




Westinghouse 


3 


78.26 


71.16 


2660.41 


80 


70 


2817.97 


2838.86 


Westinghouse 


3 


70.87 


71.10 


2061.16 


70 


70 


2036.90 




Westinghouse 


3 


69.50 


69.70 


2055.00 


70 


70 


2078.53 


2057.71 







Air 


Brake 


' Tests ^"^'3'^ 


ATSION 










TESTS 




The 


weight of the train was as follows : 






Locomotive — 






On drivers 


. . 84,100 lbs. 




On truck . 


. 34,600 lbs. 




On trailer 




. 32^300 lbs. 


Total weight 


of locomotive 






151,000 lbs. 


Tender, light weight of . 






52,800 lbs. 


Car 612, 


do. 






74,600 lbs. 


Car 619, 


do. 






76,500 lbs. 


Car 607, 


do. 






74,700 lbs. 


Car 614, 


do. 






76,500 lbs. 


Car 616, 


do. 






75,200 lbs. 


Car 121, 


do. 






72,700 lbs. 


Total weight 


Df train 






654,000 lbs. 



The coaches of this train were equipped with steel-tired wheels and 
'* Diamond S "brake shoes. 

Tests were run with two make-ups of train ; engine and 6 coaches, 
and engine and 3 coaches. The speeds obtained were 50, 60, 70, 
and 80 miles per hour ; also comparative runs between the high-speed 
and the ordinary quick-action apparatus with 70 lbs. trainpipe pressure 
were made for speeds of 70 and 80 miles per hour. 

The results of these tests are given in the following tables : 

In all of the New York tests the brake cylinder pressure of 70 lbs. 
was retained by the safety valve, resulting in a terminal braking 
power of over i i 5 per cent. For this reason the Westinghouse high- 
speed reducing valves used in the tests shown in Table XLIX., although 
set to close at 60 lbs. pressure as stated, were specially adjusted with 
reference to time required to reduce brake cylinder pressure to that point 
as to put the apparatus of both companies on substantially the same 
basis for comparison. In Table L. the train was equipped with the 
Westinghouse Company's standard apparatus. 

For the sake of ready comparison some of the results have been 
arranged as shown in the accompaning curves. Fig. 1 24 shows the 
curves of decreasing velocity from the moment that the brake was 
applied to the final stop of the train, for 8 different runs ; the horizontal 
dimensions represent the difference in feet passed over by the train after 



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0. 23: 70.86 M. P. H., 110 Lbs. T. P.jPressure, 3 Coaches 
0. 9: 78.60 M. P. H., 110 Lbs. T. P. Pressure, 3 Coaches 
0. 8: 78.26 M. P. H., 70 Lbs. T. P. Pressure, 3 Coaches 
0. 2: 70.87 M. P..H., 70 Lbs. T. P. Pressure, 3 Coaches 






















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Table L. — Tests of High-Speed Brake 

On the Central Railroad of Neiv Jersey^ Near Atsion^ Neiv Jersey ^ May and "June^ 

icpoj ; Train being Equipped ivith the TVestinghouse Air 

Brake Company'' s Standard Values. 



No. of 
Cars. 


Actual 

Speed, 

M. P. H. 


6 
6 


70.03 
69.76 


6 


70.31 


6 

6 
6 


61.43 
58.44 
59.60 


6 
6 


51.42 
49.58 


3 


76.27 


6 
6 


70.03 
70.58 


6 


70.31 



Actual 

Brake-pipe 

Pressure, 

Lbs. 



109.75 
109.80 
III. 80 

109.66 

1 10.25 
110.50 

110.25 
110.30 

100.03 

70.08 
70.00 
70.00 



Actual 
Length of 
Stop, Feet. 



1527.25 
1533.66 
1456.08 

1029.50 

935-75 
973.92 

670.41 
622.00 

1945.50 

1972.58 
1893.50 
1879.58 



Speed for 

Calculated 

Stop, 

M. P. H. 



70 
70 
70 

60 
60 
60 

50 
50 

80 

70 
70 
70 



Brake- 
pipe 
Pressure 

for 
Calculated 
Stop, Lbs. 



Length of 
Calculated 
Stop, Feet. 



iio 1522.88 
iio 1541.75 

IIO ! 1464.04 



no 

1 10 

IIO 

IIO 
IIO 



70 
70 
70 



979-44 
988.34 
990.95 

635-15 
634.08 

1974-37 

1972.73 
1862.50 
1863.04 



Average 
Length of 
Calculated 
Stop, Feet. 



1509-55 
986.24 
634.61 

1899.42 



the moment of application, and the vertical represent the speed in miles 
per hour. The 8 runs are grouped in 4 pairs, approximating 50, 60, 
70, and 80 miles per hour at the moment of application. Each pair 
is made up of a New York and Westinghouse run. The actual speeds 
of the train at the moment of application are given in the table in Fig. 
1 24, and refer to each run as marked upon the curves. 

As mentioned above, the Westinghouse tests were made to include a 
series of stops with the ordinary quick-action brake, in order to com- 
pare them with the other stops made during the tests. These are shown 
in Figs. Nos. 125 and 126, and will be of special interest in com- 
parison with similar tests made in the Absecon tests previously 
described.* 

■^ It will be noted that the Absecon tests were made to determine the relative effi- 
ciency of the quick-action and high-speed brake apparatus under similar conditions, 
without regard to whether these conditions were the best obtainable. In the Atsion 
tests the primary object in fitting up the trains w^as to have all apparatus regulated to 
give its maximum efficiency j consequently, the results in the latter tests show more 
nearly what can be obtained if the apparatus is properly and carefully maintained. 



















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ATSION 
TESTS 



Air Brake Tests ^""^'^'^ 



Fig. 125 shows the change in velocities 
of the three coach train from the moment 
of application for stops of 70 and 80 miles 
per hour. It will be noted that the length of high-speed brake stops for 
80 miles per hour is shorter than that of the quick-action stop for 70 
miles per hour. Fig. 126 contains curves similar to those of Fig. 125 
for train of engine and six coaches for initial speed of 70 miles per hour. 
Fig. 127 is of especial interest as indicating the effect upon the length 
of stop of the engine truck brake. Runs No. 118 and 1 19 were made 
with a train of engine and three coaches, the first without the truck 
brake, and the second with the same. The initial speed was 78 miles 
per hour, and the length of stop without the truck brake was 2,640 ft., 
whereas, with the truck brake, under same conditions, the stop was 
reduced to 2,440 ft., being a saving of exactly 200 ft., which is 7.7 per 
cent, decrease. This is a graphical statement of actual stops, and leaves 
no room for doubt as to the advisability of having engine truck brakes. 

Indicator Diagrains. 

High Speed Brake Applications. 




Fig. 138 Emergency 



The nature of these tests could not develop one of the most valuable 
features of the high-speed brake in service, namely, the greatly in- 
creased ability to make several full applications of the brakes without 
recharging. This feature was developed during subsequent tests, as 
well as the fact that an emergency appHcation could be produced after a 
considerably larger service reduction had been made than is possible 
with the quick-action brake. This is well shown by the cuts in 
Figures 128, 129, and 130, which are reproductions of indicator dia- 
grams taken from cylinders when in use with the high-speed appa- 
ratus. The horizontal dimensions of these diagrams represent the time 



^""^'^'^ Air Brake Tests 



ATSION 
TESTS 



in seconds and the vertical dimensions 
pressure in pounds per square inch. 

Fig. 128 shows an emergency apphca- 
tion on the high-speed brake. The cyhnder and reservoir became 
equahzed at a high pressure and the reduction was slowly effected until 
it reached the amount for which the reducing valve was set. Fig. 129 




Fig. 129 5 and 10 Lbs. Reductions. 

shows several successive service reductions in one application, and Fig. 
130 shows a service application of 1 8 lbs. reduction followed by an 
emergency. 

From table No. XLIX. it will be seen that the average length of stop 
of the high-speed apparatus was shorter than that of the New York 




15.6 Sec, 



18 Lbs. Reduction Followed 1)7 Emergency 
Fig. 130 



arrangement by from 11^ per cent, at 50 miles per hour to 10 per 
cent, at 80 miles per hour ; while for 70 miles per hour and a 6-coach 
train it was 1 8 per cent, shorter. 



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SEP 2 1904 



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